{ "dataset": "matter-materials", "schemaVersion": 2, "version": "2026-09-07", "updated": "2026-09-07", "license": "CC BY 4.0", "attribution": "Mean Free Path, Pierre F. Ribault", "canonical": "https://pierreribault.com/data/matter-materials.json", "data": { "familyLabels": { "steels-superalloys": "Steels and superalloys", "light-metals": "Light metals", "coppers": "Coppers", "refractories": "Refractories", "carbon-composites": "Carbon and composites", "ceramics-glasses": "Ceramics and glasses", "polymers-elastomers": "Polymers and elastomers", "joints-magnetics": "Joints and magnetics", "films-getters": "Films and getters", "joining-consumables": "Joining and consumables", "additive": "Additive", "liquid-metals": "Liquid metals" }, "familyOrder": [ "steels-superalloys", "light-metals", "coppers", "refractories", "carbon-composites", "ceramics-glasses", "polymers-elastomers", "joints-magnetics", "films-getters", "joining-consumables" ], "sectorLabels": { "semiconductor-equipment": "Semiconductor equipment & lithography", "semiconductor-fabs": "Chipmakers (foundries & IDMs)", "fusion-private": "Fusion, private", "big-science": "Big science (accelerators, light sources, public fusion)", "quantum": "Quantum hardware", "vacuum-electronics": "Vacuum electronics & X-ray sources", "vacuum-supply": "Vacuum equipment & components", "space-test": "Space test" }, "sectorColors": { "semiconductor-equipment": "#C8A24A", "semiconductor-fabs": "#8A4B24", "fusion-private": "#C0432A", "big-science": "#355F9E", "quantum": "#2E7D74", "vacuum-electronics": "#6E4A7E", "vacuum-supply": "#6F6A53", "space-test": "#6f83b0" }, "essaySlugByTitle": { "Everything Outgasses": "everything-outgasses", "Empty Is Not Clean": "empty-is-not-clean", "Tight Enough": "tight-enough", "The Arc": "the-arc", "The Names Nobody Cites": "the-names-nobody-cites", "The Floor Under the Fab": "the-vacuum-lock" }, "sourceRegistry": { "ohan": "O'Hanlon, A User's Guide to Vacuum Technology", "cas": "CERN Accelerator School, vacuum and materials proceedings", "cern": "CERN vacuum group compilations and coating programme", "a240": "ASTM A240 and matching alloy standards", "asm": "ASM Handbook: properties, corrosion, heat treatment", "nistc": "NIST cryogenic material properties database", "nasa": "NASA outgassing database", "ecss": "ECSS space product assurance standards", "plansee": "Plansee refractory metal and alloy data", "ctek": "CoorsTek, CeramTec, Kyocera technical ceramic data", "slack": "Slack, thermal conductivity of AlN, 1973", "saes": "SAES Getters datasheets and NEG literature", "srf": "SRF cavity preparation literature (DESY, Fermilab, JLab)", "tube": "Electron tube and ceramic-to-metal sealing practice", "kovar": "ASTM F15 and Carpenter Kovar data", "aws": "AWS Brazing Handbook; Morgan Wesgo alloy data", "honig": "Honig vapour pressure tables, RCA 1969", "semi": "Semiconductor chamber materials and plasma-resistant coating literature", "euro": "EUROfusion and international fusion materials programmes", "iter": "ITER and JET ITER-like wall programme", "kjl": "Kurt J. Lesker materials notes", "poly": "Vacuum polymer datasheets and outgassing compilations", "elast": "Elastomer supplier data and vacuum seal practice", "addm": "Additive manufacturing vacuum qualification studies", "S-EP0238433": "EP 0238433 B1, Titanium-copper-nickel braze filler metal, abstract: solidus about 925 C, liquidus about 945 C", "S-INDIUM-AUSN": "Indium Corporation, Indalloy 182 80Au/20Sn, melting 280 C, product data sheets and technical blog indium.com", "S-ITS90-CU": "H. Preston-Thomas, The International Temperature Scale of 1990 (ITS-90), Metrologia 27 (1990) 3, copper fixed point 1084.62 C, via NIST SRD 60 its90.nist.gov", "S-PAT-4409181": "US 4409181, Brazing compositions, table I (compositions Incusil 10 : 63Ag-27Cu-10In, Incusil 15 : 61.5Ag-24Cu-14.5In, Cusil 72-28)", "S-PAT-5340012": "US 5340012, Titanium hydride coated brazing product, description (temperature de brasage recommandee Incusil-ABA 715-740 C)", "S-PAT-5598966": "US 5598966, Brazed lower vacuum housing for a dewar, description (compositions Cusin-1 ABA, Palcusil-10, Ticusil, Nicoro-80 citees comme produits Wesgo)", "S-PI-AL4343": "Prince and Izant, AL 4343 (BAlSi-2), Technical Data, princeizant.com/sites/default/files/2022-09/AL_4343_BAlSi-2_TDS.pdf", "S-SANDIA-NBCU-ALUMINA": "Charles Walker, Greg Bishop, Robert Stokes, Dennis DeSmet, Sandia National Laboratories, Albuquerque, Active-brazing explosively-bonded niobium-copper to alumina ceramic, SAND2012-1595C", "S-SAPPHIRE-VIEWPORT": "Sapphire optical viewport for high pressure and temperature applications, arXiv:2106.09559 (composition 59 Ag, 27,25 Cu, 12,5 In, 1,25 Ti, melting near 700 C, oxygen-free atmosphere)", "S-STROPPA": "Stroppa et al., Calculating Joint Clearance at Brazing Temperature, Welding Journal, September 2010 (brazing ranges by AWS classification)", "S-AWS-BRAZING-HANDBOOK": "AWS Brazing Handbook, American Welding Society, chapter 3 Brazing Filler Metals and chapter 33 Electron Tubes and Vacuum Equipment", "S-WC-SELECTOR": "Wall Colmonoy Corporation, Brazing Filler Metal Selector Chart, 2019, v2.2f, f.hubspotusercontent30.net/hubfs/5229633/Wall-Colmonoy-Corp_Brazing-Filler-Metal-Selector-Chart_ENG_November2019.pdf", "S-WESGO-BAU1": "Morgan Advanced Materials, Wesgo, Data Sheet 37.5Au-62.5Cu, 06/2018, morganbrazealloys.com/media/nzrhkj5g/wesgo_375au-625cu_technical-data-sheet-2018.pdf", "S-WESGO-CUSIL": "Morgan Advanced Materials (Wesgo), Data Sheet Cusil (BAg-8), 06/2018, morganbrazealloys.com/media/bgufzxu1/wesgo_cusil_technical-data-sheet-2018.pdf", "S-WESGO-CUSIL-ABA": "Morgan Advanced Materials (Wesgo), Data Sheet Cusil-ABA, morganbrazealloys.com/media/tgnhzzfc/cusil-aba.pdf, and GlobalSpec data sheet (melting range 779-816 C)", "S-WESGO-INCUSIL10": "Morgan Advanced Materials (Wesgo), Data Sheet Incusil 10, 2018, morganbrazealloys.com/media/zqgdhp0h/wesgo_incusil-10_technical-data-sheet-2018.pdf", "S-WESGO-INCUSIL15": "Morgan Advanced Materials (Wesgo), Data Sheet Incusil 15 (BAg-29), 2018, morganbrazealloys.com/media/nqydvzcm/wesgo_incusil-15_technical-data-sheet-2018.pdf", "S-WESGO-NIORO": "Morgan Advanced Materials (Wesgo), Data Sheet Nioro (AMS 4787, BAu-4), 02/2019, morganbrazealloys.com/media/ffohjtdc/wesgo_nioro_technical-data-sheet-20190211.pdf", "S-WESGO-PALCO": "Morgan Advanced Materials (Wesgo), Data Sheet Palco (BPd-1), 06/2018, morganbrazealloys.com/media/rzupadbw/wesgo_palco_technical-data-sheet.pdf", "S-WESGO-PALCUSIL15": "Morgan Advanced Materials (Wesgo), Data Sheet Palcusil 15, 06/2018, morganbrazealloys.com/media/f24fjaxt/wesgo_palcusil-15_technical-data-sheet-2018.pdf", "S-WESGO-PALCUSIL10": "Morgan Advanced Materials, Palcusil-10 datasheet, mirrored on GlobalSpec, datasheets.globalspec.com/ds/morgan-advanced-materials-1/palcusil-10/fc3480f6-0d3d-49da-9e70-bdb1f1fc668b", "S-WESGO-CUSIN1ABA": "Morgan Advanced Materials (Wesgo), Cusin-1-ABA data sheet, morganbrazealloys.com/media/gpzjriki/cusin-1-aba.pdf", "S-WESGO-NICORO80": "Morgan Advanced Materials, Nicoro-80 datasheet, mirrored on GlobalSpec, datasheets.globalspec.com/ds/morgan-advanced-materials-1/nicoro-80/26e695fc-a3c1-4b0d-929b-cf87bd0c3f1a", "S-WESGO-TICUSIL": "Morgan Advanced Materials (Wesgo), Data Sheet Ticusil, 06/2018, morganbrazealloys.com/media/hcxpgyz5/wesgo_ticusil_technical-data-sheet-2018.pdf", "S-WP-BRAZELIST": "List of brazing alloys, Wikipedia, compiled table (BAlSi-4 : Al88Si12, solidus 577 C, liquidus 582 C)" }, "parameters": { "count": 30, "groups": { "wet_cleaning": [ "recipe", "forbidden", "limit" ], "vacuum": [ "vapor_pressure", "outgassing_unbaked_10h", "outgassing_baked", "outgassing_vacuum_fired" ], "temperature": [ "bake_assembled", "vacuum_degas", "braze_h2_firing", "metallurgical_limit" ], "thermal": [ "cte", "thermal_conductivity", "specific_heat", "melting_softening", "thermal_conductivity_cryo", "emissivity" ], "mechanical": [ "strength", "tensile", "elongation", "youngs_modulus", "density", "hardness" ], "electrical_magnetic": [ "relative_permeability", "resistivity", "dielectric_strength" ], "engineering": [ "corrosion", "joining", "availability_cost", "process_notes" ] }, "groupLabels": { "wet_cleaning": "Wet cleaning", "vacuum": "Vacuum and outgassing", "temperature": "Temperature", "thermal": "Thermal", "mechanical": "Mechanical", "electrical_magnetic": "Electrical and magnetic", "engineering": "Engineering" }, "labels": { "recipe": "Recipe", "forbidden": "Forbidden", "limit": "Limit", "vapor_pressure": "Vapour pressure", "outgassing_unbaked_10h": "Outgassing, unbaked (10 h)", "outgassing_baked": "Outgassing, baked", "outgassing_vacuum_fired": "Outgassing, vacuum fired", "bake_assembled": "Bake, assembled", "vacuum_degas": "Vacuum degas", "braze_h2_firing": "Braze / H2 firing", "metallurgical_limit": "Metallurgical limit", "cte": "CTE", "thermal_conductivity": "Thermal conductivity", "specific_heat": "Specific heat", "melting_softening": "Melting / softening", "thermal_conductivity_cryo": "Thermal conductivity (cryo)", "emissivity": "Emissivity", "strength": "Strength", "tensile": "Tensile", "elongation": "Elongation", "youngs_modulus": "Young's modulus", "density": "Density", "hardness": "Hardness", "relative_permeability": "Relative permeability", "resistivity": "Resistivity", "dielectric_strength": "Dielectric strength", "corrosion": "Corrosion", "joining": "Joining", "availability_cost": "Availability and cost", "process_notes": "Process notes" } }, "materials": [ { "id": "stainless-316ln", "symbol": "316LN", "name": "Austenitic stainless 304L / 316L / 316LN ESR", "family": "steels-superalloys", "status": "workhorse", "sectors": [ "big-science", "fusion-private", "quantum", "space-test", "vacuum-supply" ], "why": "The default wall of vacuum: weldable, bakeable past 400 C, strong, knife-edge hard, huge supply chain. L grades avoid carbide sensitization at welds; 316LN ESR stays low-permeability even welded.", "counter": "Aluminum is lighter and lower in hydrogen but too soft for knife edges and harder to weld leak-tight at scale. Titanium costs 5 to 10x.", "watchouts": "Bulk hydrogen is the outgassing floor; vacuum firing or a long air bake (oxide diffusion barrier) mitigates it.", "essays": [ "Everything Outgasses" ], "sources": [ { "label": "XHV air-bake study, arXiv 2025", "url": "https://arxiv.org/html/2512.11794v1" }, { "label": "SPS internal dump 304L vessel, CERN", "url": "https://arxiv.org/pdf/2312.15485" }, { "label": "O Hanlon, A Users Guide to Vacuum Technology" } ], "grades": [ { "g": "304L (1.4307)", "note": "general hardware and rough chambers; welds can carry delta ferrite, keep away from beams and qubits" }, { "g": "316L (1.4404)", "note": "the UHV default: chambers, CF flanges, tubing" }, { "g": "316LN (1.4429)", "note": "nitrogen strengthened, permeability under 1.005 even welded: beamlines, cryomodules, qubit hardware" }, { "g": "316LN ESR or VAR", "note": "remelted cleanliness, fewer inclusions and leak paths: cavities, He vessels, critical welds" }, { "g": "316L(N)-IG", "note": "ITER grade with controlled Co for activation: nuclear vacuum vessels" }, { "g": "316L VIM/VAR EP per SEMI F20", "note": "double melt, electropolished under 0.25 um Ra: semiconductor gas delivery" } ], "displayGrade": "316LN ESR", "propertySourceKeys": [ "ohan", "cas", "a240", "nistc", "asm" ], "properties": { "wet_cleaning": { "recipe": { "val": "alkaline degrease, DI rinse, electropolish 15–25 µm, ultrapure rinse, dry N₂; vacuum fire 950 °C for XHV", "status": "candidate" }, "forbidden": { "val": "chlorinated solvents and chloride-bearing detergents: stress corrosion cracking", "status": "candidate" }, "limit": { "val": "electropolish depth trades roughness against tolerance", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 2e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-11, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_vacuum_fired": { "val": 5e-13, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "negligible below 450 °C; Mn and Cr evaporate above ~700 °C in vacuum", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 950, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": 1050, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "solution anneal 1040–1120 °C; sensitisation 425–815 °C avoided by L grades", "status": "candidate" } }, "thermal": { "cte": { "val": 16, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 15, "unit": "W/m·K", "status": "candidate" }, "thermal_conductivity_cryo": { "val": "0.25 at 4 K", "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 500, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.15–0.25 polished, 0.6–0.8 oxidised", "status": "candidate" }, "melting_softening": { "val": "1375–1400", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "170–280 ys", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "515–620", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "40 %", "status": "candidate" }, "youngs_modulus": { "val": 193, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "150–200 HV", "status": "candidate" }, "density": { "val": 7.95, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "<1.005 annealed ESR", "status": "candidate" }, "resistivity": { "val": 74, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "excellent; pitting in hot chlorides", "status": "candidate" }, "joining": { "val": "TIG and EB weld, no preheat; brazes after nickel plating", "status": "candidate" }, "process_notes": { "val": "welds and cold work raise μr well above the certificate", "status": "candidate" }, "availability_cost": { "val": "stock in all forms; ESR to order, 2–3× cost", "status": "candidate" } } } }, { "id": "inconel-718", "symbol": "IN718", "name": "Inconel 718 / 625", "family": "steels-superalloys", "status": "workhorse", "sectors": [ "fusion-private", "big-science", "vacuum-supply" ], "why": "Keeps strength to 700 C, corrosion resistant, weldable, non-magnetic. The ARC fusion concept baselines a double-wall Inconel 718 vacuum vessel immersed in molten salt.", "counter": "Stainless yields at these temperatures and loads; titanium creeps.", "watchouts": "Expensive, slow to machine; Nb content activates under neutrons.", "essays": [], "sources": [ { "label": "Sorbom et al., ARC design, arXiv 1409.3540", "url": "https://arxiv.org/abs/1409.3540" } ], "grades": [ { "g": "718 (2.4668)", "note": "age hardened vessels and bolting" }, { "g": "625 (2.4856)", "note": "weldable, corrosion duty, bellows" }, { "g": "X-750", "note": "high temperature springs in vacuum" } ], "displayGrade": "718 aged", "propertySourceKeys": [ "asm", "tube" ], "properties": { "wet_cleaning": { "recipe": { "val": "alkaline degrease, DI rinse; pickle only with a nitric-HF qualified for the alloy", "status": "candidate" }, "forbidden": { "val": "over-pickling attacks the aged microstructure", "status": "candidate" }, "limit": { "val": "ageing oxide must come off before brazing", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 2e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-11, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "negligible", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 1000, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": 1100, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "solution 980–1065 °C then age 720/620 °C", "status": "candidate" } }, "thermal": { "cte": { "val": 13, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 11.4, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 435, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.2–0.3", "status": "candidate" }, "melting_softening": { "val": "1260–1336", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "1030 ys aged", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "1240–1400", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "12 %", "status": "candidate" }, "youngs_modulus": { "val": 200, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "380–450 HV", "status": "candidate" }, "density": { "val": 8.19, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "~1.001–1.02", "status": "candidate" }, "resistivity": { "val": 125, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "excellent, including hot", "status": "candidate" }, "joining": { "val": "weldable with strain-age cracking risk; standard braze cycles", "status": "candidate" }, "process_notes": { "val": "machining is slow and tool-hungry", "status": "candidate" }, "availability_cost": { "val": "stock, expensive", "status": "candidate" } } } }, { "id": "aluminum-6061", "symbol": "Al 6063", "name": "Aluminum 6061 / 6063 / 5083", "family": "light-metals", "status": "workhorse", "sectors": [ "big-science", "semiconductor-equipment", "semiconductor-fabs", "space-test" ], "why": "Extrudable into kilometers of complex antechamber profile, low bulk hydrogen, high conductivity spreads photon heat, non-magnetic, machines fast. The chamber metal of light sources and semiconductor process tools.", "counter": "Stainless cannot be extruded and stores far more hydrogen, but aluminum caps bakeout near 150 to 200 C and needs special welding or bimetal CF transitions.", "watchouts": "Thick porous anodizing traps water; threads gall.", "essays": [ "Empty Is Not Clean" ], "sources": [ { "label": "NEG development for MAX IV vacuum system", "url": "https://www.researchgate.net/publication/288637829_NEG_thin_film_coating_development_for_the_MAX_IV_vacuum_system" } ], "grades": [ { "g": "6061-T6", "note": "machined chamber bodies and general structure; weldable, loses temper at welds" }, { "g": "6063-T5", "note": "the extrusion grade: light source antechamber profiles by the kilometer" }, { "g": "5083-O", "note": "large welded chambers and cryo: weld-friendly, no temper to lose" }, { "g": "2219", "note": "aerospace tanks and high strength at temperature" }, { "g": "7075", "note": "avoid in baked vacuum: 5.6 percent Zn, poor weldability; mechanics only, cold, coated" } ], "displayGrade": "6063 extruded", "propertySourceKeys": [ "cern", "ohan", "asm" ], "properties": { "wet_cleaning": { "recipe": { "val": "mild alkaline or neutral detergent, DI rinse, hot dry; extrude under argon to keep the oxide thin", "status": "candidate" }, "forbidden": { "val": "sodium hydroxide attacks the metal; never anodise a UHV surface", "status": "candidate" }, "limit": { "val": "the hydrated oxide is the gas source: a thin oxide beats a clean one", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 8e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-11, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "negligible below 400 °C", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 200, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 300, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": "not-applicable", "status": "candidate", "conditions": "brazing rule R08 of src/data/brazing/brazing-rules.json: no furnace atmosphere reduces the aluminium oxide, so the process runs on a magnesium getter in a dedicated furnace and there is no hydrogen firing figure to state" }, "metallurgical_limit": { "val": "T6 temper lost above 200 °C", "status": "candidate" } }, "thermal": { "cte": { "val": 23.6, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 167, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 896, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.04–0.06 bare, 0.8 anodised", "status": "candidate" }, "melting_softening": { "val": "582–652", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "276 ys (6061-T6)", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "310", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "12 %", "status": "candidate" }, "youngs_modulus": { "val": 68.9, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "95–107 HV", "status": "candidate" }, "density": { "val": 2.7, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.000022", "status": "candidate" }, "resistivity": { "val": 4, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "good, self-passivating", "status": "candidate" }, "joining": { "val": "TIG and friction stir; brazing is difficult", "status": "candidate" }, "process_notes": { "val": "vacuum extrusion beats machining for outgassing", "status": "candidate" }, "availability_cost": { "val": "the cheapest structural metal in stock", "status": "candidate" } } } }, { "id": "titanium", "symbol": "Ti", "name": "Titanium Gr 2 / Ti-6Al-4V", "family": "light-metals", "status": "workhorse", "sectors": [ "quantum", "big-science", "space-test", "vacuum-supply" ], "why": "Hydrogen outgassing 10 to 100x below stainless: at 1e-11 Torr wall hydrogen is the residual gas, and collision-driven qubit loss follows it. Non-magnetic, half the density of steel. Monolithic Ti multi-port chambers now ship as catalog XHV products.", "counter": "Stainless is cheaper and easier to machine and weld; Ti wins when hydrogen, magnetics, or mass is the spec.", "watchouts": "Galls, poor thermal conductor, embrittles if welded dirty.", "essays": [ "Empty Is Not Clean" ], "sources": [ { "label": "Kimball Physics, quantum computing applications", "url": "https://www.kimballphysics.com/learning_center/applications-quantum-computing/" }, { "label": "Miniaturized Ti vacuum package, trapped-ion clock", "url": "https://www.researchgate.net/publication/303026452_A_highly_miniaturized_vacuum_package_for_a_trapped_ion_atomic_clock" }, { "label": "All-titanium single-ion clock vacuum system", "url": "https://arxiv.org/pdf/2504.13071" } ], "grades": [ { "g": "Gr 1", "note": "softest CP grade: deep drawn and formed parts" }, { "g": "Gr 2", "note": "CP workhorse: chambers, low hydrogen stock" }, { "g": "Gr 5 (Ti-6Al-4V)", "note": "strength: flanges, printed chambers, structural" }, { "g": "Gr 23 (Ti-6Al-4V ELI)", "note": "extra-low interstitial for cryogenic toughness and AM powder" }, { "g": "Ti-Mo 85/15 wire", "note": "titanium sublimation pump filaments" } ], "displayGrade": "Gr 2", "propertySourceKeys": [ "asm", "saes" ], "properties": { "wet_cleaning": { "recipe": { "val": "alkaline degrease, DI rinse, nitric-HF pickle to strip the alpha case, ultrapure rinse", "status": "candidate" }, "forbidden": { "val": "chlorinated solvents: stress corrosion cracking; unbuffered HF over-etches", "status": "candidate" }, "limit": { "val": "alpha case depth from any prior hot work", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 1e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-12, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "negligible below 1000 °C", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 500, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 750, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": 900, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "β transus 882 °C (Gr 2)", "status": "candidate" } }, "thermal": { "cte": { "val": 8.6, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 17, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 523, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.2", "status": "candidate" }, "melting_softening": { "val": "1668", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "275 ys (Gr2) / 830 (Gr5)", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "345 / 950", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "20 %", "status": "candidate" }, "youngs_modulus": { "val": 105, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "145–160 HV", "status": "candidate" }, "density": { "val": 4.51, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.00005", "status": "candidate" }, "resistivity": { "val": 52, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "outstanding", "status": "candidate" }, "joining": { "val": "TIG under full argon shielding; Ti-based braze fillers", "status": "candidate" }, "process_notes": { "val": "galls badly; getters O and N above 400 °C", "status": "candidate" }, "availability_cost": { "val": "stock, moderate premium", "status": "candidate" } } } }, { "id": "beryllium", "symbol": "Be", "name": "Beryllium", "family": "light-metals", "status": "workhorse", "sectors": [ "vacuum-electronics", "big-science" ], "why": "Lowest-Z structural metal: near transparent to X-rays while holding one bar. X-ray tube exit windows and detector beam pipes.", "counter": "Aluminum absorbs too much at low energy; polymer windows creep and permeate; diamond costs more per square centimeter.", "watchouts": "Toxic dust, licensed machining. Exiting fusion first walls since 2023.", "essays": [ "The Names Nobody Cites" ], "sources": [ { "label": "ITER blanket, first wall material change", "url": "https://www.iter.org/machine/blanket" }, { "label": "JET ITER-like wall, Juelich", "url": "https://www.fz-juelich.de/en/ifn/ifn-1/forschung/jet-iter-like-wall" } ], "grades": [ { "g": "PF-60, IF-1 foil", "note": "X-ray window grades, thin foil transparency" }, { "g": "S-65", "note": "structural and first wall heritage grade (JET, ITER original baseline)" }, { "g": "S-200F", "note": "general structural beryllium" } ], "displayGrade": "S-200F", "propertySourceKeys": [ "iter", "asm" ], "properties": { "wet_cleaning": { "recipe": { "val": "wet machining and wet cleaning only, in a controlled enclosure with captured effluent", "status": "candidate" }, "forbidden": { "val": "ANY dry operation: the dust is the hazard, not the metal", "status": "candidate" }, "limit": { "val": "the occupational exposure limit, not vacuum performance", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 2e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-11, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "negligible below 1000 °C", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 250, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 750, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": 900, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "oxidises above 700 °C in air", "status": "candidate" } }, "thermal": { "cte": { "val": 11.5, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 200, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 1825, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.1 polished", "status": "candidate" }, "melting_softening": { "val": "1287", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "240 ys", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "320", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "2–3 %", "status": "candidate" }, "youngs_modulus": { "val": 303, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "~150 HV", "status": "candidate" }, "density": { "val": 1.85, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "diamagnetic", "status": "candidate" }, "resistivity": { "val": 4, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "oxide-passivated; attacked by chlorides", "status": "candidate" }, "joining": { "val": "brazed with Al-Si; welding is specialist", "status": "candidate" }, "process_notes": { "val": "chronic beryllium disease risk governs every step", "status": "candidate" }, "availability_cost": { "val": "restricted, licensed handling", "status": "candidate" } } } }, { "id": "copper-ofe", "symbol": "Cu OFE", "name": "Oxygen-free copper C10100 / C10200", "family": "coppers", "status": "workhorse", "sectors": [ "big-science", "vacuum-electronics", "quantum", "vacuum-supply" ], "why": "Survives hydrogen brazing without embrittlement, best cheap thermal and electrical conductor, soft enough to seal a CF knife edge. Gaskets, RF structures, cryostat stages (gold-plated at millikelvin).", "counter": "ETP copper blisters in hydrogen brazing; aluminum gaskets do not seal knife edges reliably.", "watchouts": "Soft, creeps, anneals during bake; silver-plate gaskets above 400 C against sticking.", "essays": [ "Tight Enough" ], "sources": [ { "label": "CERN Accelerator School, vacuum proceedings", "url": "https://cas.web.cern.ch" } ], "grades": [ { "g": "C10100 (OFE, 99.99)", "note": "hydrogen-braze safe, RF and gasket reference grade" }, { "g": "C10200 (OF, 99.95)", "note": "general OF hardware where C10100 certs are overkill" }, { "g": "C11000 (ETP)", "note": "banned from hydrogen brazing and vacuum firing: oxygen blisters" }, { "g": "C14500 (TeCu)", "note": "free machining via tellurium: acceptable, but confirm on the drawing, never for brazing-critical parts" } ], "displayGrade": "C10100 OFE", "propertySourceKeys": [ "cas", "nistc", "asm", "ohan" ], "properties": { "wet_cleaning": { "recipe": { "val": "alkaline degrease, DI rinse, citric or sulphamic bright dip, ultrapure rinse, dry N₂, assemble within the hour", "status": "candidate" }, "forbidden": { "val": "chlorine-bearing etchants; hydrogen firing on ETP grades: blistering", "status": "candidate" }, "limit": { "val": "the fresh surface re-oxidises in minutes, so cleaning is scheduled against assembly, not against a spec", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 1e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 5e-12, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "negligible below 700 °C", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 400, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 600, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": 1000, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "recrystallises from 200 °C", "status": "candidate" } }, "thermal": { "cte": { "val": 16.5, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 391, "unit": "W/m·K", "status": "candidate" }, "thermal_conductivity_cryo": { "val": "~2000 at 4 K, RRR 100", "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 385, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.03–0.05 polished, 0.6 oxidised", "status": "candidate" }, "melting_softening": { "val": "1085", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "70 ys annealed", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "220", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "45 %", "status": "candidate" }, "youngs_modulus": { "val": 117, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "40–60 HV annealed", "status": "candidate" }, "density": { "val": 8.96, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "0.999994 diamagnetic", "status": "candidate" }, "resistivity": { "val": 1.71, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "oxidises in air, inert in vacuum", "status": "candidate" }, "joining": { "val": "brazes and EB welds; the CF gasket is a cold seal", "status": "candidate" }, "process_notes": { "val": "never handle bare after cleaning", "status": "candidate" }, "availability_cost": { "val": "C10100 to order, C10200 in stock", "status": "candidate" } } } }, { "id": "cucrzr-glidcop", "symbol": "CuCrZr", "name": "CuCrZr and GlidCop (dispersion-strengthened Cu)", "family": "coppers", "status": "workhorse", "sectors": [ "big-science", "fusion-private" ], "why": "Copper conductivity with real mechanical strength that survives brazing and bake cycles: photon absorbers, divertor heat-sink tubes, collimator cooling.", "counter": "Pure copper loses all strength annealed; stainless cannot evacuate the heat flux.", "watchouts": "CuCrZr needs controlled heat-treatment windows; GlidCop is hard to weld.", "essays": [], "sources": [ { "label": "SPS internal dump, CuCr1Zr cooled absorbers", "url": "https://arxiv.org/pdf/2312.15485" } ], "grades": [ { "g": "CuCr1Zr (C18150), ITER-grade IG", "note": "heat sink tubes and RF: strength depends on the exact solution-age window" }, { "g": "GlidCop AL-15 (C15715)", "note": "dispersion strengthened, survives braze cycles unannealed: photon absorbers" }, { "g": "GlidCop AL-25 (C15725)", "note": "more oxide, more strength, less conductivity: pick per heat flux" } ], "displayGrade": "CuCrZr", "propertySourceKeys": [ "cas", "asm", "cern" ], "properties": { "wet_cleaning": { "recipe": { "val": "as OFE: degrease, DI, mild bright dip, ultrapure rinse", "status": "candidate" }, "forbidden": { "val": "aggressive etch attacks the Cr-Zr precipitates and the alumina dispersion", "status": "candidate" }, "limit": { "val": "keep any thermal step below the ageing temperature, or re-age", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 1e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 5e-12, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "negligible", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 600, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": 980, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "CuCrZr ageing 460–500 °C; GlidCop does not recrystallise", "status": "candidate" } }, "thermal": { "cte": { "val": 17, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": "320 CuCrZr, 365 GlidCop", "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 390, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.05 polished", "status": "candidate" }, "melting_softening": { "val": "1070–1083", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "300–400 ys", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "450–500", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "12–15 %", "status": "candidate" }, "youngs_modulus": { "val": 130, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "120–140 HV", "status": "candidate" }, "density": { "val": 8.9, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "~1.0", "status": "candidate" }, "resistivity": { "val": 2.1, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "as copper", "status": "candidate" }, "joining": { "val": "brazes; GlidCop keeps its strength through the cycle", "status": "candidate" }, "process_notes": { "val": "GlidCop is not fusion-weldable in the usual sense", "status": "candidate" }, "availability_cost": { "val": "to order; GlidCop single source", "status": "candidate" } } } }, { "id": "tungsten", "symbol": "W", "name": "Tungsten", "family": "refractories", "status": "workhorse", "sectors": [ "fusion-private", "big-science", "vacuum-electronics", "semiconductor-equipment" ], "why": "Highest melting point of any metal, low sputtering, low tritium retention. Since the 2023 rebaseline it is the ITER first wall armor, about 600 square meters, aligning ITER with every downstream reactor concept.", "counter": "Beryllium, the original baseline, lost on toxicity, erosion dust, tritium co-deposition, and melting in disruptions. 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Rotating anode discs, grids, furnace hardware. 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This is an open materials war.", "essays": [ "The Floor Under the Fab" ], "sources": [ { "label": "Tin the enabler, hydrogen diffusion into ruthenium", "url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6359073/" }, { "label": "DIFFER, Hotel Ruthenium", "url": "https://www.differ.nl/news/hotel-ruthenium-how-hydrogen-checks-in-but-never-leaves" }, { "label": "Chen, oxidation, outgassing and blistering in EUV", "url": "https://frederickchen.substack.com/p/oxidation-outgassing-and-blistering" } ], "grades": [ { "g": "Sputtered Ru, about 2 nm", "note": "the production cap: oxidation block versus EUV absorption trade" }, { "g": "Alloyed and oxide caps (research)", "note": "candidates against blistering and Sn uptake, not production" } ], "displayGrade": "2 nm Ru cap", "propertySourceKeys": [ "semi" ], "properties": { "wet_cleaning": { "recipe": { "val": "hydrogen radical cleaning in situ, not wet cleaning: the standard EUV method for removing carbon", "status": "candidate" }, "forbidden": { "val": "any wet chemistry on a multilayer; hydrogen also causes blistering, the current research problem", "status": "candidate" }, "limit": { "val": "the trade between carbon removal and hydrogen-induced blistering", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 5e-10, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 5e-13, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "negligible", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 400, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": "substrate", "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "oxidises to volatile RuO₄ under oxidising plasma", "status": "candidate" } }, "thermal": { "cte": { "val": 6.4, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 117, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 238, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.2", "status": "candidate" }, "melting_softening": { "val": "2334", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "coating", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" }, "youngs_modulus": { "val": 447, "unit": "GPa", "status": "candidate" }, "density": { "val": 12.45, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "~1.0", "status": "candidate" }, "resistivity": { "val": 7.1, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "oxidation resistant in the EUV environment", "status": "candidate" }, "joining": { "val": "magnetron sputtered, nm scale", "status": "candidate" }, "process_notes": { "val": "hydrocarbon partial pressure is its enemy, not outgassing", "status": "candidate" }, "availability_cost": { "val": "inside the EUV supply chain only", "status": "candidate" } } } }, { "id": "boron-conditioning", "symbol": "B", "name": "Boron and lithium wall conditioning", "family": "films-getters", "status": "workhorse", "sectors": [ "fusion-private", "big-science" ], "why": "Sacrificial gettering films (boronization by diborane, lithium evaporation) buy oxygen pumping and low recycling that a tungsten wall no longer provides for free.", "counter": "Permanent getters cannot survive plasma contact: the consumable film is the design.", "watchouts": "An operations discipline, not a component: chemistry per campaign.", "essays": [], "sources": [ { "label": "IAEA FEC 2025 synopsis, W wall and boronization", "url": "https://conferences.iaea.org/event/392/contributions/35653/attachments/19727/33779/IAEA2025-synopsis_Change_of_wall_material_for_IDM%20(1).pdf" } ], "grades": [ { "g": "Diborane diluted in He, glow discharge", "note": "the ITER-class boronization consumable" }, { "g": "Li evaporation", "note": "low recycling campaigns, spherical tokamak and stellarator practice" }, { "g": "B powder injection (impurity powder dropper)", "note": "real-time boronization without glow discharge: DIII-D, ASDEX-U, EAST practice" } ], "displayGrade": "boronisation", "propertySourceKeys": [ "iter", "euro" ], "properties": { "wet_cleaning": { "recipe": { "val": "not applicable: the wall is conditioned in situ by glow discharge or evaporation, not washed", "status": "candidate" }, "forbidden": { "val": "the whole point is that you cannot open the machine to clean it", "status": "candidate" }, "limit": { "val": "campaign length, and the tritium inventory the film retains", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": "pumps hydrogen and oxygen", "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "lithium evaporates readily, which is the mechanism", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": "in-vessel, machine dependent", "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "the film is consumed and reapplied each campaign", "status": "candidate" } }, "thermal": { "melting_softening": { "val": "2076 (B)", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "film", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" }, "density": { "val": 2.34, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" } }, "engineering": { "joining": { "val": "deposited on the whole inner wall", "status": "candidate" }, "process_notes": { "val": "a consumable surface, renewed between campaigns", "status": "candidate" }, "availability_cost": { "val": "tokamak practice", "status": "candidate" } } } }, { "id": "zinc-brass", "symbol": "Zn", "name": "Zinc, and therefore brass", "family": "joints-magnetics", "status": "banned", "sectors": [], "why": "Vapor pressure reaches the 1e-7 mbar range near bake temperatures: it metallizes the system and poisons cathodes and optics.", "counter": "Brass fittings smuggled in from plumbing suppliers; galvanized fasteners.", "essays": [], "sources": [ { "label": "Honig vapor pressure tables, RCA 1969" }, { "label": "O Hanlon, A Users Guide to Vacuum Technology" } ], "displayGrade": "brass C36000", "propertySourceKeys": [ "honig", "ohan" ], "properties": { "wet_cleaning": { "recipe": { "val": "not applicable", "status": "candidate" }, "forbidden": { "val": "the material itself", "status": "candidate" }, "limit": { "val": "vapour pressure", "status": "candidate" } }, "vacuum": { "vapor_pressure": { "val": "THE CONDEMNING NUMBER: Zn reaches 1e-6 Torr vapour pressure near 250 °C, so it evaporates during a routine bakeout and plates itself onto everything colder", "status": "candidate" } }, "thermal": { "cte": { "val": 20.5, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 120, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 380, "unit": "J/kg·K", "status": "candidate" }, "melting_softening": { "val": "900–940", "unit": "°C", "status": "candidate" } }, "mechanical": { "youngs_modulus": { "val": 100, "unit": "GPa", "status": "candidate" }, "density": { "val": 8.5, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "~1.0", "status": "candidate" }, "resistivity": { "val": 6.4, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "availability_cost": { "val": "everywhere, which is the danger", "status": "candidate" } } } }, { "id": "cadmium", "symbol": "Cd", "name": "Cadmium plating", "family": "joints-magnetics", "status": "banned", "sectors": [], "why": "Sublimes in vacuum, whiskers, toxic: on every prohibited-materials list in space and UHV practice.", "counter": "Vintage aerospace fasteners and old mil-spec hardware.", "essays": [], "sources": [ { "label": "ECSS space product assurance standards", "url": "https://ecss.nl" }, { "label": "NASA outgassing database", "url": "https://outgassing.nasa.gov" } ], "displayGrade": "Cd plate", "propertySourceKeys": [ "honig", "ecss", "nasa" ], "properties": { "wet_cleaning": { "recipe": { "val": "not applicable", "status": "candidate" }, "forbidden": { "val": "the material itself", "status": "candidate" }, "limit": { "val": "vapour pressure, and occupational law", "status": "candidate" } }, "vacuum": { "vapor_pressure": { "val": "THE CONDEMNING NUMBER: 1e-6 Torr near 180 °C, lower than zinc, and cadmium is a category 1B carcinogen", "status": "candidate" } }, "thermal": { "cte": { "val": 30.8, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 97, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 230, "unit": "J/kg·K", "status": "candidate" }, "melting_softening": { "val": 321, "unit": "°C", "status": "candidate" } }, "mechanical": { "youngs_modulus": { "val": 50, "unit": "GPa", "status": "candidate" }, "density": { "val": 8.65, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "~1.0", "status": "candidate" }, "resistivity": { "val": 7.3, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "availability_cost": { "val": "banned by RoHS and the space standards", "status": "candidate" } } } }, { "id": "lead-solder", "symbol": "SnPb", "name": "Lead and standard solder joints", "family": "joints-magnetics", "status": "banned", "sectors": [], "why": "Marginal vapor pressure, creep, and flux residues that outgas forever.", "counter": "Ad hoc electrical joints: use crimps, spot welds, or vacuum-rated solder practice.", "essays": [], "sources": [ { "label": "O Hanlon, A Users Guide to Vacuum Technology" } ], "displayGrade": "63Sn-37Pb", "propertySourceKeys": [ "ohan" ], "properties": { "wet_cleaning": { "recipe": { "val": "if it must be present: ultrasonic flux removal in IPA, then a long bake", "status": "candidate" }, "forbidden": { "val": "no-clean flux, which is not vacuum-clean", "status": "candidate" }, "limit": { "val": "flux residue, which outgasses far longer than the alloy", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 5e-8, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": "not bakeable", "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "lead evaporates slowly above 300 °C, but the flux is the real problem", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 80, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": "183 reflow", "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "THE CONDEMNING NUMBER: melts at 183 °C, so it caps the bakeout of every system it touches", "status": "candidate" } }, "thermal": { "cte": { "val": 25, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 50, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 180, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.1", "status": "candidate" }, "melting_softening": { "val": 183, "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "30–50 tens", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "30–50", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "30 %", "status": "candidate" }, "youngs_modulus": { "val": 30, "unit": "GPa", "status": "candidate" }, "density": { "val": 8.4, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "~1.0", "status": "candidate" }, "resistivity": { "val": 15, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "joining": { "val": "soldered", "status": "candidate" }, "process_notes": { "val": "present in legacy feedthroughs and assemblies", "status": "candidate" }, "availability_cost": { "val": "commodity", "status": "candidate" } } } }, { "id": "free-machining-steel", "symbol": "303", "name": "Free-machining steels (303, 12L14)", "family": "steels-superalloys", "status": "banned", "sectors": [], "why": "Sulfur and lead stringers create leak paths through welds and porosity.", "counter": "The machine shops default bar stock: specify 304L or 316L explicitly on every drawing.", "essays": [ "Tight Enough" ], "sources": [ { "label": "O Hanlon, A Users Guide to Vacuum Technology" } ], "displayGrade": "303", "propertySourceKeys": [ "ohan", "asm" ], "properties": { "wet_cleaning": { "recipe": { "val": "not applicable", "status": "candidate" }, "forbidden": { "val": "the sulphur inclusions, which also nucleate corrosion pits", "status": "candidate" }, "limit": { "val": "composition", "status": "candidate" } }, "vacuum": { "vapor_pressure": { "val": "THE CONDEMNING MECHANISM: sulphur (303) or lead (12L14) added for chip breaking, both volatile, both destroying weldability", "status": "candidate" } }, "thermal": { "cte": { "val": 17.3, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 16, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 500, "unit": "J/kg·K", "status": "candidate" }, "melting_softening": { "val": "1400", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "240", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "620", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "40 %", "status": "candidate" }, "youngs_modulus": { "val": 193, "unit": "GPa", "status": "candidate" }, "density": { "val": 8, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "magnetic", "status": "candidate" }, "resistivity": { "val": 72, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "worse than 304 despite being stainless", "status": "candidate" }, "joining": { "val": "not weldable to vacuum quality", "status": "candidate" }, "availability_cost": { "val": "the default bar stock in every machine shop, which is exactly the hazard", "status": "candidate" } } } }, { "id": "mild-steel", "symbol": "Fe", "name": "Mild steel and cast iron, bare", "family": "steels-superalloys", "status": "banned", "sectors": [], "why": "Porosity, rust, water retention, magnetic.", "counter": "Acceptable painted or plated in rough vacuum housings, nowhere beyond.", "essays": [], "sources": [ { "label": "O Hanlon, A Users Guide to Vacuum Technology" } ], "displayGrade": "mild steel", "propertySourceKeys": [ "ohan" ], "properties": { "wet_cleaning": { "recipe": { "val": "not applicable in UHV", "status": "candidate" }, "forbidden": { "val": "aqueous anything: it rusts while you rinse it", "status": "candidate" }, "limit": { "val": "THE CONDEMNING MECHANISM: rust is hydrated and porous, an inexhaustible water reservoir, and cast iron is porous throughout", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": "1e-7 rusted", "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "THE CONDEMNING MECHANISM: porous hydrated rust is a bottomless water reservoir; every bakeout drives it off and it re-forms on air exposure, so base pressure never settles", "status": "candidate" } }, "thermal": { "cte": { "val": 12, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 50, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 450, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.7 oxidised", "status": "candidate" }, "melting_softening": { "val": "1500", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "250", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "400", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "25 %", "status": "candidate" }, "youngs_modulus": { "val": 200, "unit": "GPa", "status": "candidate" }, "density": { "val": 7.87, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "ferromagnetic", "status": "candidate" }, "resistivity": { "val": 10, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "poor", "status": "candidate" }, "joining": { "val": "weldable", "status": "candidate" }, "availability_cost": { "val": "cheap and everywhere", "status": "candidate" } } } }, { "id": "ptfe", "symbol": "PTFE", "name": "PTFE (Teflon)", "family": "polymers-elastomers", "status": "banned", "sectors": [], "why": "Cold flow under clamp load, high permeation, radiation damage. Not banned everywhere, rationed everywhere.", "counter": "Scroll pump tip seals (a known particle and outgassing source), limited wire insulation.", "essays": [], "sources": [ { "label": "NASA outgassing database", "url": "https://outgassing.nasa.gov" } ], "displayGrade": "virgin PTFE", "propertySourceKeys": [ "nasa", "ohan" ], "properties": { "wet_cleaning": { "recipe": { "val": "IPA wipe, then bake", "status": "candidate" }, "forbidden": { "val": "using it as a structural seal, which is the actual ban", "status": "candidate" }, "limit": { "val": "creep, not chemistry", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 1e-7, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "low; fluorinated fragments above 260 °C", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 200, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 200, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "THE CONDEMNING MECHANISM: cold flow under any sustained load, far below its 327 °C melt", "status": "candidate" } }, "thermal": { "cte": { "val": 135, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 0.25, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 1000, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.9", "status": "candidate" }, "melting_softening": { "val": 327, "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "20–35 tens", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "20–35", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "200–400 %", "status": "candidate" }, "youngs_modulus": { "val": 0.5, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "50–55 Shore D", "status": "candidate" }, "density": { "val": 2.2, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" }, "resistivity": { "val": ">1e18 Ω·cm", "status": "candidate" }, "dielectric_strength": { "val": "60 kV/mm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "inert to essentially everything", "status": "candidate" }, "joining": { "val": "not bondable without etching", "status": "candidate" }, "process_notes": { "val": "fine as wire insulation, never as a gasket", "status": "candidate" }, "availability_cost": { "val": "commodity", "status": "candidate" } } } }, { "id": "silicones", "symbol": "Si-O", "name": "Silicones", "family": "polymers-elastomers", "status": "banned", "sectors": [], "why": "Migrate as monolayers over everything, wreck adhesion, optics, and wire bonding; some crack under electron beams into conductive residue.", "counter": "Operators hands, RTV brought in for a quick fix, some O-ring lubes.", "essays": [], "sources": [ { "label": "ECSS space product assurance standards", "url": "https://ecss.nl" } ], "displayGrade": "silicone grease and RTV", "propertySourceKeys": [ "ecss", "nasa", "ohan" ], "properties": { "wet_cleaning": { "recipe": { "val": "not applicable", "status": "candidate" }, "forbidden": { "val": "its presence anywhere in the building, honestly", "status": "candidate" }, "limit": { "val": "contamination is irreversible: the RGA signature at m/z 73, 147 and 207 never fully leaves", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": "1e-5 and it migrates", "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "THE CONDEMNING MECHANISM: cyclic siloxanes migrate over every surface in the system, and once cracked in a plasma or an electron beam they leave an insulating SiO₂ film nothing removes", "status": "candidate" } }, "thermal": { "cte": { "val": 300, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 0.2, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 1500, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.9", "status": "candidate" } }, "mechanical": { "strength": { "val": "5–10 tens", "unit": "MPa", "status": "candidate" }, "youngs_modulus": { "val": 0.005, "unit": "GPa", "status": "candidate" }, "density": { "val": 1.1, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" } }, "engineering": { "availability_cost": { "val": "everywhere, and that is the problem", "status": "candidate" } } } }, { "id": "std-elastomers", "symbol": "NBR", "name": "Standard elastomers (Buna-N, EPDM)", "family": "polymers-elastomers", "status": "banned", "sectors": [], "why": "Plasticizer outgassing and high permeation.", "counter": "Fine in rough vacuum, banned beyond.", "essays": [], "sources": [ { "label": "NASA outgassing database", "url": "https://outgassing.nasa.gov" } ], "displayGrade": "NBR", "propertySourceKeys": [ "ohan", "nasa" ], "properties": { "wet_cleaning": { "recipe": { "val": "IPA wipe if used in rough vacuum", "status": "candidate" }, "forbidden": { "val": "expecting it to survive a bake", "status": "candidate" }, "limit": { "val": "the temperature ceiling", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 0.000005, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": "not bakeable", "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "continuous plasticiser evolution", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 100, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "THE CONDEMNING NUMBER: 100–120 °C maximum, so no real bakeout is possible, on top of the worst outgassing rate in common use", "status": "candidate" } }, "thermal": { "cte": { "val": 230, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 0.25, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 1900, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.9", "status": "candidate" } }, "mechanical": { "strength": { "val": "10–20 tens", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "10–20", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "300–500 %", "status": "candidate" }, "youngs_modulus": { "val": 0.005, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "70–80 Shore A", "status": "candidate" }, "density": { "val": 1.2, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" } }, "engineering": { "corrosion": { "val": "poor against ozone and oxidisers", "status": "candidate" }, "joining": { "val": "compressed in a groove", "status": "candidate" }, "process_notes": { "val": "rough vacuum only", "status": "candidate" }, "availability_cost": { "val": "the cheapest seal there is", "status": "candidate" } } } }, { "id": "pvc-nylon", "symbol": "PVC", "name": "PVC, nylon, acrylic", "family": "polymers-elastomers", "status": "banned", "sectors": [], "why": "Plasticizers, water, monomers.", "counter": "Cable jackets and quick brackets that never got reviewed.", "essays": [], "sources": [ { "label": "NASA outgassing database", "url": "https://outgassing.nasa.gov" } ], "displayGrade": "PVC", "propertySourceKeys": [ "nasa", "ohan" ], "properties": { "wet_cleaning": { "recipe": { "val": "not applicable", "status": "candidate" }, "forbidden": { "val": "nylon in particular: it comes out of the bath heavier than it went in", "status": "candidate" }, "limit": { "val": "water absorption", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": "1e-5 to 1e-6", "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "PVC plasticiser is continuous; nylon holds several percent water by mass", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 60, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "THE CONDEMNING MECHANISM: plasticiser for PVC, water absorption for nylon, and PVC releases chloride that attacks stainless", "status": "candidate" } }, "thermal": { "cte": { "val": 70, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 0.19, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 1000, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.9", "status": "candidate" } }, "mechanical": { "strength": { "val": "50 tens", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "50", "unit": "MPa", "status": "candidate" }, "youngs_modulus": { "val": 3, "unit": "GPa", "status": "candidate" }, "density": { "val": 1.4, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" } }, "engineering": { "availability_cost": { "val": "commodity", "status": "candidate" } } } }, { "id": "anodized-al-uhv", "symbol": "AlOx", "name": "Anodized aluminum inside UHV", "family": "light-metals", "status": "banned", "sectors": [], "why": "The porous oxide is a water reservoir. 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Pushed by the Chinese light source program on the CERN lineage.", "essays": [], "sources": [ { "label": "TiZrHfV activation by XPS, NIM-A", "url": "https://www.sciencedirect.com/science/article/abs/pii/S0168900220303661" } ], "displayGrade": "TiZrHfV", "propertySourceKeys": [ "cern", "saes" ], "properties": { "wet_cleaning": { "recipe": { "val": "substrate cleaned before coating; the film is never wet-cleaned", "status": "candidate" }, "forbidden": { "val": "venting cycles beyond the qualified count", "status": "candidate" }, "limit": { "val": "activation capacity", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": "pumps", "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": "pumps", "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "none", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 200, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 200, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "activation 150–180 °C, lower than TiZrV", "status": "candidate" } }, "thermal": { "cte": { "val": "substrate", "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": "substrate", "unit": "W/m·K", "status": "candidate" } }, "mechanical": { "strength": { "val": "coating", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" }, "density": { "val": "~6", "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "~1.0", "status": "candidate" } }, "engineering": { "joining": { "val": "sputtered in situ", "status": "candidate" }, "process_notes": { "val": "the hafnium lowers activation further", "status": "candidate" }, "availability_cost": { "val": "research and pilot installations", "status": "candidate" } } } }, { "id": "amorphous-carbon", "symbol": "a-C", "name": "Amorphous carbon coatings", "family": "films-getters", "status": "future", "maturity": "deployed", "sectors": [ "big-science" ], "why": "Secondary electron yield near 1 with no activation bake: electron cloud suppression where you cannot heat.", "counter": "Deployed in the SPS and part of the HL-LHC toolkit, with years of beam exposure and no degradation. 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Pushed by CERN and STFC.", "essays": [], "sources": [ { "label": "HL-LHC project", "url": "https://hilumilhc.web.cern.ch" } ], "displayGrade": "LESS on Cu", "propertySourceKeys": [ "cern", "cas" ], "properties": { "wet_cleaning": { "recipe": { "val": "open question: the structured surface traps cleaning fluid and particles by design", "status": "candidate" }, "forbidden": { "val": "none noted", "status": "candidate" }, "limit": { "val": "the trade at the heart of the technique: the roughness that kills SEY also multiplies surface area", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": "rises with area, falls after bake", "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "none", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": "substrate", "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "substrate", "status": "candidate" } }, "thermal": { "cte": { "val": "substrate", "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": "substrate", "unit": "W/m·K", "status": "candidate" }, "emissivity": { "val": "raised deliberately, up to 0.9", "status": "candidate" } }, "mechanical": { "strength": { "val": "surface", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "substrate", "status": "candidate" } }, "engineering": { "joining": { "val": "laser textured in place", "status": "candidate" }, "process_notes": { "val": "SEY below 1 without any coating", "status": "candidate" }, "availability_cost": { "val": "CERN programme", "status": "candidate" } } } }, { "id": "am-ti-alsi", "symbol": "AM Ti", "name": "Printed chambers: Ti-6Al-4V, AlSi10Mg", "family": "additive", "status": "future", "maturity": "tested", "sectors": [ "quantum", "big-science" ], "why": "Topology-optimized monolithic UHV chambers, 70 percent lighter: printed titanium holds low 1e-10 mbar with outgassing indistinguishable from a conventional flange, and 2-year vacuum holds are demonstrated.", "counter": "Driven by quantum sensor programs (Birmingham and Nottingham lineage) and commercial chamber makers.", "watchouts": "Porosity and virtual leaks are process-control problems, largely solved for LPBF.", "essays": [ "Tight Enough" ], "sources": [ { "label": "Vovrosh et al., AM flange and shielding, Sci Rep 2018", "url": "https://www.nature.com/articles/s41598-018-20352-x" }, { "label": "AM UHV chamber for portable quantum technologies", "url": "https://www.researchgate.net/publication/349328637_Additively_manufactured_ultra-high_vacuum_chamber_for_portable_quantum_technologies" }, { "label": "AM for advanced quantum technologies, review", "url": "https://arxiv.org/pdf/2503.11570" } ], "displayGrade": "Ti-6Al-4V SLM", "propertySourceKeys": [ "addm" ], "properties": { "wet_cleaning": { "recipe": { "val": "HIP, then machine the sealing faces, then chemical polish internal surfaces if access allows, then bake long", "status": "candidate" }, "forbidden": { "val": "trusting an as-built internal surface; 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niobium SLM under development at CERN. 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Pushed by the ceramic majors.", "essays": [], "sources": [ { "label": "Y-based coating stability studies", "url": "https://www.mdpi.com/2079-6412/9/2/102" } ], "displayGrade": "sintered Y₂O₃", "propertySourceKeys": [ "semi" ], "properties": { "wet_cleaning": { "recipe": { "val": "as a dense ceramic: solvent, DI rinse, bake", "status": "candidate" }, "forbidden": { "val": "none noted", "status": "candidate" }, "limit": { "val": "unlike the sprayed coating, there is no porosity to trap fluid", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 1e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-12, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "none", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 1000, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "stable to 1500 °C", "status": "candidate" } }, "thermal": { "cte": { "val": 8, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 13, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 450, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.8", "status": "candidate" }, "melting_softening": { "val": 2410, "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "150–200 flex", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" }, "youngs_modulus": { "val": 170, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "1200 HV", "status": "candidate" }, "density": { "val": 5.03, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" }, "resistivity": { "val": ">1e14 Ω·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "plasma resistant without the coating porosity", "status": "candidate" }, "process_notes": { "val": "the bulk answer to coating particulation", "status": "candidate" }, "availability_cost": { "val": "emerging", "status": "candidate" } } } }, { "id": "cvd-diamond", "symbol": "C*", "name": "CVD diamond windows", "family": "ceramics-glasses", "status": "future", "maturity": "deployed", "sectors": [ "big-science", "fusion-private", "vacuum-electronics" ], "why": "X-ray and RF windows at power densities beryllium cannot survive, with extreme thermal conductivity: synchrotron and XFEL optics, gyrotron windows for fusion heating.", "counter": "Commercial at small apertures, growing. 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Pushed by the EU fusion program and Japan.", "essays": [], "sources": [ { "label": "EUROfusion materials program", "url": "https://euro-fusion.org" } ], "displayGrade": "EUROFER97", "propertySourceKeys": [ "euro" ], "properties": { "wet_cleaning": { "recipe": { "val": "not established for fusion service", "status": "candidate" }, "forbidden": { "val": "none noted", "status": "candidate" }, "limit": { "val": "activation constrains composition, which constrains everything else", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": "insufficient data", "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": "insufficient data", "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "negligible", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 1000, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "tempering 750 °C; service limited to ~550 °C", "status": "candidate" } }, "thermal": { "cte": { "val": 11, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 29, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 490, "unit": "J/kg·K", "status": "candidate" }, "melting_softening": { "val": "1450", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "450–550 ys", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "600–700", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "20 %", "status": "candidate" }, "youngs_modulus": { "val": 217, "unit": "GPa", "status": "candidate" }, "density": { "val": 7.8, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "ferromagnetic", "status": "candidate" } }, "engineering": { "corrosion": { "val": "moderate", "status": "candidate" }, "joining": { "val": "weldable", "status": "candidate" }, "process_notes": { "val": "reduced activation is the entire design driver", "status": "candidate" }, "availability_cost": { "val": "programme quantities", "status": "candidate" } } } }, { "id": "sicsic", "symbol": "SiC/SiC", "name": "SiC/SiC composites", "family": "ceramics-glasses", "status": "future", "maturity": "lab", "sectors": [ "fusion-private" ], "why": "Flow channel inserts and blanket internals: chemistry-compatible with liquid metals and lead-lithium, low activation, high temperature.", "counter": "Irradiation database growing; joining and hermeticity remain the thesis topics. 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Pushed by Juelich and EU labs.", "essays": [], "sources": [ { "label": "Juelich plasma-facing materials", "url": "https://www.fz-juelich.de/en/ifn/ifn-1/forschung/jet-iter-like-wall" } ], "displayGrade": "Wf/W", "propertySourceKeys": [ "euro" ], "properties": { "wet_cleaning": { "recipe": { "val": "not established", "status": "candidate" }, "forbidden": { "val": "none noted", "status": "candidate" }, "limit": { "val": "interface integrity", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": "insufficient data", "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": "insufficient data", "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "as tungsten", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 1500, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "as W, with the interface as the weak point", "status": "candidate" } }, "thermal": { "cte": { "val": 4.5, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": "~150", "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 132, "unit": "J/kg·K", "status": "candidate" }, "melting_softening": { "val": 3422, "unit": "°C", "status": "candidate" } }, "mechanical": { "elongation": { "val": "pseudo-ductile", "status": "candidate" }, "density": { "val": "~18", "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "~1.0", "status": "candidate" } }, "engineering": { "process_notes": { "val": "solving the brittleness that limits bulk tungsten", "status": "candidate" }, "availability_cost": { "val": "research", "status": "candidate" } } } }, { "id": "liquid-li-sn", "symbol": "Li/Sn", "name": "Liquid metal PFCs (Li, Sn, capillary porous systems)", "family": "liquid-metals", "status": "future", "maturity": "tested", "sectors": [ "fusion-private" ], "why": "Self-healing plasma-facing surfaces: erosion stops being a lifetime limit, and vapor shielding self-regulates transients.", "counter": "CPS tin divertor concept designs published for EU-DEMO; tokamak tests (FTU lineage, NSTX-U lithium program) accumulating. Pushed by EU-DEMO design teams, PPPL, and DIFFER.", "watchouts": "Tin: three roles in this table (EUV source, EUV contaminant, fusion wall).", "essays": [], "sources": [ { "label": "Liquid metal PFC progress review, 2024", "url": "https://www.sciencedirect.com/science/article/pii/S2352179124001996" }, { "label": "CPS liquid tin divertor for EU-DEMO", "url": "https://link.springer.com/article/10.1007/s10894-020-00263-4" }, { "label": "US liquid metal PFC program report", "url": "https://www.osti.gov/servlets/purl/2587499" } ], "displayGrade": "liquid Li CPS", "propertySourceKeys": [ "euro" ], "properties": { "wet_cleaning": { "recipe": { "val": "not applicable: the surface renews itself, which is the entire idea", "status": "candidate" }, "forbidden": { "val": "water, violently, for lithium", "status": "candidate" }, "limit": { "val": "vapour pressure into the plasma, and tritium retention in lithium", "status": "candidate" } }, "vacuum": { "vapor_pressure": { "val": "THE governing number: Li reaches 1e-4 Torr near 500 °C, Sn far lower, which is why tin is gaining", "status": "candidate" } }, "temperature": { "metallurgical_limit": { "val": "Li melts 181 °C, Sn 232 °C", "status": "candidate" } }, "thermal": { "melting_softening": { "val": "181 / 232", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "liquid", "unit": "MPa", "status": "candidate" }, "density": { "val": "0.53 Li, 7.3 Sn", "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" } }, "engineering": { "joining": { "val": "capillary porous substrate", "status": "candidate" }, "process_notes": { "val": "a self-healing wall", "status": "candidate" }, "availability_cost": { "val": "research", "status": "candidate" } } } }, { "id": "ald-barriers", "symbol": "ALD", "name": "ALD alumina and aluminide barriers", "family": "films-getters", "status": "future", "maturity": "tested", "sectors": [ "fusion-private", "semiconductor-equipment" ], "why": "Tritium and hydrogen permeation barriers on steel, and conformal coatings inside complex parts.", "counter": "Coating-on-steel demonstrations; integration into blanket designs. Pushed by fusion programs and the ALD industry.", "essays": [], "sources": [ { "label": "EUROfusion materials program", "url": "https://euro-fusion.org" } ], "displayGrade": "ALD Al₂O₃", "propertySourceKeys": [ "euro", "semi" ], "properties": { "wet_cleaning": { "recipe": { "val": "substrate cleaned to semiconductor standard before deposition", "status": "candidate" }, "forbidden": { "val": "particles: one particle is one pinhole", "status": "candidate" }, "limit": { "val": "PRF of 1e3 to 1e5 depends entirely on defect density", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": "reduces substrate outgassing", "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "none", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": "substrate", "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "substrate", "status": "candidate" } }, "thermal": { "cte": { "val": "substrate", "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": "substrate", "unit": "W/m·K", "status": "candidate" } }, "mechanical": { "strength": { "val": "coating", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" }, "density": { "val": 3, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" }, "resistivity": { "val": ">1e14 Ω·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "excellent barrier", "status": "candidate" }, "joining": { "val": "conformal, coats internal geometry", "status": "candidate" }, "process_notes": { "val": "tritium permeation barrier, and outgassing barrier", "status": "candidate" }, "availability_cost": { "val": "emerging in fusion and accelerator programmes", "status": "candidate" } } } }, { "id": "nb3sn-films", "symbol": "Nb3Sn", "name": "Nb3Sn films on copper cavities", "family": "films-getters", "status": "future", "maturity": "tested", "sectors": [ "big-science" ], "why": "SRF at 4.2 K instead of 2 K: deletes a cryoplant stage.", "counter": "Single-cell records improving yearly; not yet a machine baseline. 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Crucibles and evaporation boats, heaters, noble-diode ion pump cathodes, and since 2021 the qubit film that tripled transmon coherence on sapphire.", "counter": "Tungsten is stiffer but brittle and unweldable in practice; molybdenum embrittles at welds. Ta pays its price tag back in fabricability.", "watchouts": "Drinks hydrogen above 300 C: embrittles if heated in poor vacuum.", "essays": [], "sources": [ { "label": "Place et al., tantalum transmon platform, 2021", "url": "https://arxiv.org/abs/2003.00024" }, { "label": "Kurt Lesker materials notes", "url": "https://www.lesker.com" } ], "grades": [ { "g": "R05200 (pure Ta)", "note": "crucibles, heaters, liners" }, { "g": "R05252 (Ta-2.5W)", "note": "strength at temperature" }, { "g": "Sputtered alpha-Ta film", "note": "transmon qubit electrodes on sapphire" } ], "displayGrade": "pure Ta", "propertySourceKeys": [ "plansee", "asm", "kjl" ], "properties": { "wet_cleaning": { "recipe": { "val": "degrease and DI rinse; nitric-HF etch where the surface matters, as in transmon work", "status": "candidate" }, "forbidden": { "val": "hydrogen furnaces: it absorbs H and embrittles", "status": "candidate" }, "limit": { "val": "surface oxide quality, which is what the qubit work is chasing", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 1e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-12, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "negligible below 2200 °C", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 1600, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": 2000, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "recrystallises ~1100 °C", "status": "candidate" } }, "thermal": { "cte": { "val": 6.5, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 57, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 140, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.1", "status": "candidate" }, "melting_softening": { "val": "3017", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "165–200 ys", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "200–300", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "25–40 %", "status": "candidate" }, "youngs_modulus": { "val": 186, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "90–120 HV", "status": "candidate" }, "density": { "val": 16.65, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "~1.0", "status": "candidate" }, "resistivity": { "val": 13.5, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "immune to almost everything below 150 °C", "status": "candidate" }, "joining": { "val": "EB welds beautifully", "status": "candidate" }, "process_notes": { "val": "the transmon platform metal since 2021, for its stable oxide", "status": "candidate" }, "availability_cost": { "val": "expensive, to order", "status": "candidate" } } } }, { "id": "rhenium-wre", "symbol": "W-Re", "name": "Rhenium and W-Re / Mo-Re alloys", "family": "refractories", "status": "workhorse", "sectors": [ "vacuum-electronics" ], "why": "Rhenium buys ductility and thermal-fatigue resistance in refractories: W-Re focal tracks resist crazing on rotating anodes, W-Re wires make C-type thermocouples to 2300 C.", "counter": "Pure tungsten tracks craze early and the spectrum drifts; pure Mo joints crack.", "watchouts": "Cost: rhenium is one of the rarest stable elements.", "essays": [], "sources": [ { "label": "Plansee refractory alloy data", "url": "https://www.plansee.com" } ], "grades": [ { "g": "W-5Re / W-26Re", "note": "anode focal tracks and thermocouple pairs" }, { "g": "Mo-47.5Re", "note": "ductile weldable refractory assemblies" } ], "displayGrade": "W-25Re", "propertySourceKeys": [ "plansee" ], "properties": { "wet_cleaning": { "recipe": { "val": "degrease, DI rinse, hydrogen fire", "status": "candidate" }, "forbidden": { "val": "oxidising conditions hot: Re₂O₇ is volatile and toxic", "status": "candidate" }, "limit": { "val": "oxide volatility, not cleanliness", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 1e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-12, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "negligible below 2200 °C", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 1500, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": 1800, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "no DBTT problem: that is the point of the rhenium", "status": "candidate" } }, "thermal": { "cte": { "val": 4.8, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": "70–100", "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 150, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.1", "status": "candidate" }, "melting_softening": { "val": "3000–3180", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "1000+ ys", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "1200–1800", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "10–20 %", "status": "candidate" }, "youngs_modulus": { "val": "400–460", "unit": "GPa", "status": "candidate" }, "hardness": { "val": "400–500 HV", "status": "candidate" }, "density": { "val": "19.7 (W-25Re)", "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "~1.0", "status": "candidate" }, "resistivity": { "val": "25–30", "status": "candidate" } }, "engineering": { "corrosion": { "val": "inert in vacuum", "status": "candidate" }, "joining": { "val": "brazed; 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201 low carbon for high temperature" }, { "g": "Sulfamate electroplate", "note": "low stress braze-prep plating on metallized ceramics" }, { "g": "Electroless NiP (high phosphorus)", "note": "conformal corrosion coat on Al process chambers; higher P is less magnetic" } ], "displayGrade": "Nickel 200", "propertySourceKeys": [ "asm", "tube", "kjl" ], "properties": { "wet_cleaning": { "recipe": { "val": "alkaline degrease then DI rinse; activate immediately before brazing", "status": "candidate" }, "forbidden": { "val": "letting a plated part sit oxidised before the braze cycle", "status": "candidate" }, "limit": { "val": "plating porosity traps rinse water: bake before assembly", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 2e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-11, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "negligible below 900 °C", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 900, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": 1100, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "Curie 358 °C", "status": "candidate" } }, "thermal": { "cte": { "val": 13.3, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 70, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 456, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.1 polished", "status": "candidate" }, "melting_softening": { "val": "1455", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "148 ys", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "462", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "45 %", "status": "candidate" }, "youngs_modulus": { "val": 207, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "~110 HV", "status": "candidate" }, "density": { "val": 8.9, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "ferromagnetic", "status": "candidate" }, "resistivity": { "val": 9.5, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "good; alkali resistant", "status": "candidate" }, "joining": { "val": "the wetting layer that makes stainless brazeable", "status": "candidate" }, "process_notes": { "val": "electroless NiP carries phosphorus that changes braze behaviour", "status": "candidate" }, "availability_cost": { "val": "plating is a standard shop service", "status": "candidate" } } } }, { "id": "fastener-alloys", "symbol": "A286", "name": "UHV fastener alloys", "family": "steels-superalloys", "status": "workhorse", "sectors": [ "big-science", "quantum", "space-test", "vacuum-supply" ], "why": "Bolting is where UHV builds actually fail: galling, seized threads, trapped volumes. 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the binder corrodes first", "status": "candidate" }, "joining": { "val": "machinable, unlike pure W", "status": "candidate" }, "process_notes": { "val": "the machinable dense shielding material", "status": "candidate" }, "availability_cost": { "val": "to drawing", "status": "candidate" } } } }, { "id": "aln-shapal", "symbol": "AlN", "name": "Aluminum nitride and Shapal", "family": "ceramics-glasses", "status": "workhorse", "sectors": [ "semiconductor-equipment", "vacuum-electronics", "quantum" ], "why": "The insulator that conducts heat: ESC bodies and heaters, laser diode mounts, anywhere alumina would cook.", "counter": "Alumina conducts 25 to 30 W per meter kelvin; AlN runs 170 plus. 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oxidises in air above 800 °C", "status": "candidate" } }, "thermal": { "cte": { "val": 4.5, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": "170–200 polycrystalline, 285–320 single crystal", "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 740, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.8", "status": "candidate" }, "melting_softening": { "val": "2200 dec.", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "300–350 flex", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" }, "youngs_modulus": { "val": 330, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "1100–1200 HV", "status": "candidate" }, "density": { "val": 3.26, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" }, "resistivity": { "val": ">1e13 Ω·cm", "status": "candidate" }, "dielectric_strength": { "val": "14–17 kV/mm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "hydrolyses in humid air", "status": "candidate" }, "joining": { "val": "active-alloy brazed or metallised", "status": "candidate" }, "process_notes": { "val": "Shapal is the machinable grade at lower κ", "status": "candidate" }, "availability_cost": { "val": "Maruwa, Tokuyama, Precision Ceramics", "status": "candidate" } } } }, { "id": "macor", "symbol": "Macor", "name": "Macor machinable glass-ceramic", "family": "ceramics-glasses", "status": "workhorse", "sectors": [ "quantum", "big-science", "vacuum-supply" ], "why": "Mill it Tuesday, bake it Wednesday: the prototyping insulator, stable to 800 C, CTE close to hard glasses so it mounts optics without cracking them.", "counter": "Alumina is stronger and cleaner but needs grinding; PEEK dies at bake temperatures.", "watchouts": "Weaker than fired ceramics; not for high load or high voltage margins.", "essays": [], "sources": [ { "label": "Ion trap with in-vacuum optics, Macor mounts", "url": "https://arxiv.org/html/2310.07058v2" }, { "label": "Corning Macor data", "url": "https://www.corning.com" } ], "grades": [ { "g": "Macor (Corning MGC)", "note": "the single canonical grade" } ], "displayGrade": "Macor", "propertySourceKeys": [ "ctek" ], "properties": { "wet_cleaning": { "recipe": { "val": "solvent degrease then long bake: machined surfaces are porous and hold cutting fluid", "status": "candidate" }, "forbidden": { "val": "cutting fluid left in the pores; aqueous soak", "status": "candidate" }, "limit": { "val": "machined porosity, so the bake matters more than the wash", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 5e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 5e-12, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "none", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 800, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "continuous 800 °C, softens 1000 °C", "status": "candidate" } }, "thermal": { "cte": { "val": 9.3, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 1.46, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 790, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.9", "status": "candidate" }, "melting_softening": { "val": "1000 soft.", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "94 flex", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" }, "youngs_modulus": { "val": 66.9, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "250 HV", "status": "candidate" }, "density": { "val": 2.52, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" }, "resistivity": { "val": ">1e14 Ω·cm", "status": "candidate" }, "dielectric_strength": { "val": "40 kV/mm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "good", "status": "candidate" }, "joining": { "val": "not brazeable; mechanically clamped", "status": "candidate" }, "process_notes": { "val": "machines on a normal lathe, which is its whole point", "status": "candidate" }, "availability_cost": { "val": "Corning, stock bar and plate", "status": "candidate" } } } }, { "id": "beo", "symbol": "BeO", "name": "Beryllia", "family": "ceramics-glasses", "status": "workhorse", "sectors": [ "vacuum-electronics" ], "why": "The tube industry thermal insulator: BeO moves heat like a metal while holding kilovolts, under collectors and high dissipation grids.", "counter": "AlN has replaced it where it can, but BeO still wins on raw conductivity and heritage designs.", "watchouts": "Toxic as dust: machining is licensed, priced accordingly.", "essays": [], "sources": [ { "label": "Materion beryllia data", "url": "https://www.materion.com" } ], "grades": [ { "g": "BeO 99.5 (Thermalox class)", "note": "standard high conductivity insulator grade" } ], "displayGrade": "99.5 % BeO", "propertySourceKeys": [ "ctek", "tube" ], "properties": { "wet_cleaning": { "recipe": { "val": "wet processes only, in a controlled enclosure, effluent captured", "status": "candidate" }, "forbidden": { "val": "ANY dry operation that can raise dust", "status": "candidate" }, "limit": { "val": "occupational exposure, full stop", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 1e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-12, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "none", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 1200, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": 1500, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "service to 1800 °C", "status": "candidate" } }, "thermal": { "cte": { "val": 7.5, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 270, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 1030, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.7", "status": "candidate" }, "melting_softening": { "val": "2507", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "250 flex", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" }, "youngs_modulus": { "val": 345, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "1200 HV", "status": "candidate" }, "density": { "val": 3.01, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" }, "resistivity": { "val": ">1e14 Ω·cm", "status": "candidate" }, "dielectric_strength": { "val": "12–14 kV/mm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "inert", "status": "candidate" }, "joining": { "val": "metallised and brazed", "status": "candidate" }, "process_notes": { "val": "dust is a chronic inhalation hazard", "status": "candidate" }, "availability_cost": { "val": "restricted, declining supply", "status": "candidate" } } } }, { "id": "pbn", "symbol": "PBN", "name": "Pyrolytic boron nitride", "family": "ceramics-glasses", "status": "workhorse", "sectors": [ "semiconductor-equipment", "big-science" ], "why": "The crucible of epitaxy: CVD-grown, binder-free, nothing to outgas into an MBE melt. Effusion cells, coating boats, high purity liners.", "counter": "Graphite crucibles shed carbon into III-V melts; alumina reacts with aggressive charges.", "watchouts": "Anisotropic: strong in plane, cleaves between layers.", "essays": [], "sources": [ { "label": "Momentive PBN data", "url": "https://www.momentive.com" } ], "grades": [ { "g": "PBN (CVD)", "note": "effusion cells and liners" }, { "g": "PBN/PG composite heaters", "note": "integrated heater-crucible stacks" } ], "displayGrade": "PBN", "propertySourceKeys": [ "ctek" ], "properties": { "wet_cleaning": { "recipe": { "val": "solvent wipe and dry only", "status": "candidate" }, "forbidden": { "val": "aqueous cleaning of a heater assembly: any trapped moisture is fatal at power", "status": "candidate" }, "limit": { "val": "the CVD deposit is pore-free, so cleaning is a wipe, not a process", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 5e-10, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 5e-13, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "none", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 1400, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": 1600, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "stable to 2000 °C in vacuum or inert", "status": "candidate" } }, "thermal": { "cte": { "val": "1.0 in-plane, 20 through", "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": "60 in-plane, 2 through", "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 800, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.9", "status": "candidate" }, "melting_softening": { "val": "2973 sub.", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "150–200 flex", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" }, "youngs_modulus": { "val": "25–50", "unit": "GPa", "status": "candidate" }, "density": { "val": 2.15, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" }, "resistivity": { "val": ">1e14 Ω·cm", "status": "candidate" }, "dielectric_strength": { "val": "50–100 kV/mm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "inert; unlike hot-pressed BN it is not hygroscopic", "status": "candidate" }, "joining": { "val": "clamped or CVD-integrated with graphite heaters", "status": "candidate" }, "process_notes": { "val": "the pore-free crystalline form; do not confuse it with hot-pressed BN", "status": "candidate" }, "availability_cost": { "val": "Momentive, to drawing", "status": "candidate" } } } }, { "id": "quartz-semi", "symbol": "Qz", "name": "Semiconductor quartzware", "family": "ceramics-glasses", "status": "workhorse", "sectors": [ "semiconductor-equipment", "semiconductor-fabs" ], "why": "Furnace tubes, boats, bell jars, plasma windows: fused quartz is the transparent consumable of the fab.", "counter": "Ceramics are opaque and metals contaminate; quartz is pure SiO2, its erosion is process-native on silicon.", "watchouts": "Devitrifies with cycling and alkali contamination; OH content sets the IR and thermal behavior.", "essays": [], "sources": [ { "label": "Heraeus fused silica data", "url": "https://www.heraeus.com" } ], "grades": [ { "g": "GE 214 class", "note": "standard low-OH furnace grade" }, { "g": "Heraeus HSQ / Suprasil", "note": "purity and optical grades per position" } ], "displayGrade": "synthetic fused quartz", "propertySourceKeys": [ "semi" ], "properties": { "wet_cleaning": { "recipe": { "val": "the fab standard: HF etch to strip deposits and the devitrified skin, DI cascade rinse, dry", "status": "candidate" }, "forbidden": { "val": "letting devitrification advance: the part crazes and sheds", "status": "candidate" }, "limit": { "val": "HF etch budget: each clean removes wall, and the part has a countable number of cleans", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 1e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-12, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "none", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 1000, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": 1200, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "devitrifies above 1200 °C in service", "status": "candidate" } }, "thermal": { "cte": { "val": 0.55, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 1.4, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 740, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.9", "status": "candidate" }, "melting_softening": { "val": "1665 soft.", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "50 flex", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" }, "youngs_modulus": { "val": 73, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "600–700 HV", "status": "candidate" }, "density": { "val": 2.2, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" }, "resistivity": { "val": ">1e18 Ω·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "inert except HF", "status": "candidate" }, "joining": { "val": "flame-worked", "status": "candidate" }, "process_notes": { "val": "a consumable with a finite service life", "status": "candidate" }, "availability_cost": { "val": "commodity in the fab supply chain", "status": "candidate" } } } }, { "id": "crystal-windows", "symbol": "CaF2", "name": "Crystal window materials", "family": "ceramics-glasses", "status": "workhorse", "sectors": [ "quantum", "big-science", "space-test", "semiconductor-equipment" ], "why": "When fused silica stops transmitting: MgF2 and CaF2 open the VUV, ZnSe and Ge open the IR. Laser windows, spectroscopy ports, cryostat optical access.", "counter": "Silica cuts off near 170 nm and past 3.5 um; sapphire covers much but not the VUV edge or the deep IR.", "watchouts": "Soft, hygroscopic edges (MgF2 less so), thermal shock limits; ZnSe is toxic to machine.", "essays": [], "sources": [ { "label": "Kurt Lesker viewport materials notes", "url": "https://www.lesker.com" } ], "grades": [ { "g": "MgF2 VUV grade", "note": "transmits to 120 nm: excimer and Lyman alpha" }, { "g": "CaF2 excimer grade", "note": "193 nm lithography and UV laser duty" }, { "g": "ZnSe CVD", "note": "CO2 laser and broadband IR" }, { "g": "Ge", "note": "long-wave IR, opaque visible" } ], "displayGrade": "CaF₂", "propertySourceKeys": [ "kjl" ], "properties": { "wet_cleaning": { "recipe": { "val": "dry solvent drag-wipe only, methanol or acetone on lens tissue", "status": "candidate" }, "forbidden": { "val": "water: CaF₂ and especially KBr are soluble; ultrasonics", "status": "candidate" }, "limit": { "val": "solubility, which rules out every aqueous step", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 1e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-12, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "none", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 150, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 200, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "cleaves and cracks under thermal shock", "status": "candidate" } }, "thermal": { "cte": { "val": 18.9, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 9.7, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 854, "unit": "J/kg·K", "status": "candidate" }, "melting_softening": { "val": "1418", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "36 flex", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" }, "youngs_modulus": { "val": 76, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "160 HV", "status": "candidate" }, "density": { "val": 3.18, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" }, "resistivity": { "val": ">1e14 Ω·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "water-soluble to varying degrees by material", "status": "candidate" }, "joining": { "val": "indium or elastomer sealed, never brazed", "status": "candidate" }, "process_notes": { "val": "high CTE and low strength make sealing the hard part", "status": "candidate" }, "availability_cost": { "val": "optics suppliers, standard sizes", "status": "candidate" } } } }, { "id": "silicon-parts", "symbol": "Si", "name": "Single-crystal silicon parts", "family": "ceramics-glasses", "status": "workhorse", "sectors": [ "semiconductor-equipment", "semiconductor-fabs" ], "why": "The consumable that matches the wafer: etch electrodes, focus and edge rings machined from CZ ingot, eroding into nothing the process minds.", "counter": "Any metal ring contaminates; SiC costs more and is reserved for hotter, longer-life positions.", "watchouts": "Resistivity and dopant are process parameters, not details: specify them.", "essays": [ "The Floor Under the Fab" ], "sources": [ { "label": "Y-based coatings and Si ceramics in plasma tools", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC5535249/" } ], "grades": [ { "g": "CZ silicon, low resistivity doped", "note": "RF-coupled electrodes and rings" }, { "g": "High purity float zone", "note": "where metallic background matters most" } ], "displayGrade": "float zone", "propertySourceKeys": [ "semi" ], "properties": { "wet_cleaning": { "recipe": { "val": "RCA: SC-1 for particles and organics, HF dip to strip oxide, SC-2 for metals, ultrapure cascade rinse, spin dry", "status": "candidate" }, "forbidden": { "val": "any metallic contamination in the bath: Cu and Fe diffuse in and kill devices", "status": "candidate" }, "limit": { "val": "metal contamination measured in atoms per cm², the tightest cleaning spec in industry", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 5e-10, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 5e-13, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "negligible below 1200 °C", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 1000, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": 1200, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "melts 1414 °C", "status": "candidate" } }, "thermal": { "cte": { "val": 2.6, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 150, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 700, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.6", "status": "candidate" }, "melting_softening": { "val": "1414", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "165 flex", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" }, "youngs_modulus": { "val": 130, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "1000 HV", "status": "candidate" }, "density": { "val": 2.33, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "diamagnetic", "status": "candidate" }, "resistivity": { "val": "doping dependent", "status": "candidate" }, "dielectric_strength": { "val": "30 kV/mm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "oxide-passivated", "status": "candidate" }, "joining": { "val": "anodic and fusion bonding", "status": "candidate" }, "process_notes": { "val": "the RCA clean is the reference every other wet bench descends from", "status": "candidate" }, "availability_cost": { "val": "commodity by diameter", "status": "candidate" } } } }, { "id": "carbon-family", "symbol": "C", "name": "Graphite, pyrolytic graphite, glassy carbon", "family": "carbon-composites", "status": "workhorse", "sectors": [ "big-science", "vacuum-electronics", "semiconductor-equipment", "fusion-private" ], "why": "Low-Z, refractory, machinable: beam dumps and strike surfaces, rotating anode heat sinks, tube grids (PG), crucibles, heater elements. 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graphite dusts.", "watchouts": "Brittle; joining is clamping, not brazing, in most designs.", "essays": [], "sources": [ { "label": "European XFEL photon transport design reports" }, { "label": "CERN Accelerator School, beam intercepting devices", "url": "https://cas.web.cern.ch" } ], "grades": [ { "g": "Hot pressed B4C", "note": "apertures and absorber tiles" }, { "g": "Enriched B-10 grades", "note": "neutron duty" } ], "displayGrade": "hot-pressed B₄C", "propertySourceKeys": [ "cas", "semi" ], "properties": { "wet_cleaning": { "recipe": { "val": "solvent and DI rinse, dry; hot-pressed grades have residual porosity so bake after", "status": "candidate" }, "forbidden": { "val": "oxidising cleaners hot", "status": "candidate" }, "limit": { "val": "porosity of the grade", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 5e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 5e-12, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "none", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 1200, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": 1500, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "oxidises above 600 °C in air", "status": "candidate" } }, "thermal": { "cte": { "val": 5, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": "30–40", "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 950, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.9", "status": "candidate" }, "melting_softening": { "val": "2450", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "350–400 flex", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" }, "youngs_modulus": { "val": 450, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "2800–3200 HV", "status": "candidate" }, "density": { "val": 2.52, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" }, "resistivity": { "val": "0.1–10 Ω·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "good", "status": "candidate" }, "joining": { "val": "clamped; 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The step-braze ladder is the architecture of every tube.", "counter": "Welding cannot join ceramic to metal; adhesives cannot hold bake, voltage, or decades.", "watchouts": "Every alloy in the ladder must clear the vapor pressure bar: no Zn, no Cd bearing brazes, ever, whatever the plumbing catalog says.", "essays": [ "Tight Enough" ], "sources": [ { "label": "AWS Brazing Handbook" }, { "label": "Morgan Advanced Materials, Wesgo alloys data", "url": "https://www.morganadvancedmaterials.com" } ], "grades": [ { "g": "Cusil / BAg-8 (Ag72Cu28), 780 C", "note": "the eutectic workhorse on Mo-Mn plus Ni metallization", "properties": { "temperature": { "braze_h2_firing": { "val": 780, "unit": "°C", "status": "candidate", "source": "S-WESGO-CUSIL", "conditions": "solidus, congruent melting" } }, "thermal": { "cte": { "val": 19.6, "unit": "ppm/K", "status": "candidate", "source": "S-WESGO-CUSIL", "conditions": "over 20-850 C" } }, "mechanical": { "strength": { "val": 272, "unit": "MPa", "status": "candidate", "source": "S-WESGO-CUSIL", "conditions": "filler yield strength, not a joint strength" } } } }, { "g": "Nioro / BAu-4 / AMS 4787 (Au82Ni18), 955 C", "note": "first joints of step-brazed stacks, corrosion duty", "properties": { "temperature": { "braze_h2_firing": { "val": 955, "unit": "°C", "status": "candidate", "source": "S-WESGO-NIORO", "conditions": "solidus, congruent melting" } }, "thermal": { "cte": { "val": 17.5, "unit": "ppm/K", "status": "candidate", "source": "S-WESGO-NIORO", "conditions": "over 20-850 C" } }, "mechanical": { "strength": { "val": 686, "unit": "MPa", "status": "candidate", "source": "S-WESGO-NIORO", "conditions": "filler yield strength, not a joint strength" } } } }, { "g": "Ticusil (Ag68.8Cu26.7Ti4.5), 780-900 C", "note": "direct ceramic wetting, no metallization step", "properties": { "temperature": { "braze_h2_firing": { "val": "780-900", "unit": "°C", "status": "candidate", "source": "S-WESGO-TICUSIL", "conditions": "solidus to liquidus" } }, "thermal": { "cte": { "val": 18.5, "unit": "ppm/K", "status": "candidate", "source": "S-WESGO-TICUSIL", "conditions": "over 20-500 C" } }, "mechanical": { "strength": { "val": 292, "unit": "MPa", "status": "candidate", "source": "S-WESGO-TICUSIL", "conditions": "filler yield strength, not a joint strength" } } } }, { "g": "Cusil-ABA (Ag63Cu35.25Ti1.75), 779-816 C", "note": "direct ceramic wetting, no metallization step", "properties": { "temperature": { "braze_h2_firing": { "val": "779-816", "unit": "°C", "status": "candidate", "source": "S-WESGO-CUSIL-ABA", "conditions": "solidus to liquidus" } } } }, { "g": "Incusil-ABA / APA-7 (Ag59Cu27.25In12.5Ti1.25), 715-740 C", "note": "the low step: joins after everything else is closed", "properties": { "temperature": { "braze_h2_firing": { "val": "715-740", "unit": "°C", "status": "candidate", "source": "S-PAT-5340012", "conditions": "recommended brazing window" } } } }, { "g": "Cusin-1 ABA (Ag63Cu34.25Ti1.75Sn1), 775-806 C", "note": "Ag-Cu-Sn-Ti titanium-active braze filler, solidus to liquidus 775-806 C", "properties": { "temperature": { "braze_h2_firing": { "val": "775-806", "unit": "°C", "status": "candidate", "source": "S-WESGO-CUSIN1ABA", "conditions": "solidus to liquidus" } } } }, { "g": "Palcusil 15 (Ag65Cu20Pd15), 850-900 C", "note": "Ag-Cu-Pd braze filler, solidus to liquidus 850-900 C", "properties": { "temperature": { "braze_h2_firing": { "val": "850-900", "unit": "°C", "status": "candidate", "source": "S-WESGO-PALCUSIL15", "conditions": "solidus to liquidus" } }, "mechanical": { "strength": { "val": 379, "unit": "MPa", "status": "candidate", "source": "S-WESGO-PALCUSIL15", "conditions": "filler yield strength, not a joint strength" } } } }, { "g": "Palcusil 10 (Ag58Cu32Pd10), 824-852 C", "note": "Ag-Cu-Pd braze filler, solidus to liquidus 824-852 C", "properties": { "temperature": { "braze_h2_firing": { "val": "824-852", "unit": "°C", "status": "candidate", "source": "S-WESGO-PALCUSIL10", "conditions": "solidus to liquidus" } } } }, { "g": "Palco / BPd-1 (Pd65Co35), 1219 C", "note": "Pd-Co braze filler, solidus, congruent melting 1219 C", "properties": { "temperature": { "braze_h2_firing": { "val": 1219, "unit": "°C", "status": "candidate", "source": "S-WESGO-PALCO", "conditions": "solidus, congruent melting" } }, "thermal": { "cte": { "val": 17, "unit": "ppm/K", "status": "candidate", "source": "S-WESGO-PALCO", "conditions": "over 20-1000 C" } }, "mechanical": { "strength": { "val": 344, "unit": "MPa", "status": "candidate", "source": "S-WESGO-PALCO", "conditions": "filler yield strength, not a joint strength" } } } }, { "g": "Incusil 15 / BAg-29 (Ag61.5Cu24In14.5), 605-725 C", "note": "Ag-Cu-In braze filler, solidus to liquidus 605-725 C", "properties": { "temperature": { "braze_h2_firing": { "val": "605-725", "unit": "°C", "status": "candidate", "source": "S-WESGO-INCUSIL15", "conditions": "solidus to liquidus" } }, "thermal": { "cte": { "val": 18.5, "unit": "ppm/K", "status": "candidate", "source": "S-WESGO-INCUSIL15", "conditions": "over 20-500 C" } }, "mechanical": { "strength": { "val": 386, "unit": "MPa", "status": "candidate", "source": "S-WESGO-INCUSIL15", "conditions": "filler yield strength, not a joint strength" } } } }, { "g": "Incusil 10 (Ag63Cu27In10), 685-730 C", "note": "Ag-Cu-In braze filler, solidus to liquidus 685-730 C", "properties": { "temperature": { "braze_h2_firing": { "val": "685-730", "unit": "°C", "status": "candidate", "source": "S-WESGO-INCUSIL10", "conditions": "solidus to liquidus" } }, "thermal": { "cte": { "val": 19.58, "unit": "ppm/K", "status": "candidate", "source": "S-WESGO-INCUSIL10", "conditions": "over 20-500 C" } }, "mechanical": { "strength": { "val": 345, "unit": "MPa", "status": "candidate", "source": "S-WESGO-INCUSIL10", "conditions": "filler yield strength, not a joint strength" } } } }, { "g": "Nicoro-80 (Au81.5Cu16.5Ni2), 910-925 C", "note": "Au-Cu-Ni braze filler, solidus to liquidus 910-925 C", "properties": { "temperature": { "braze_h2_firing": { "val": "910-925", "unit": "°C", "status": "candidate", "source": "S-WESGO-NICORO80", "conditions": "solidus to liquidus" } } } }, { "g": "Indalloy 182 / 80Au/20Sn (Au80Sn20), 280 C", "note": "Au-Sn solder, solidus, congruent melting 280 C", "properties": { "temperature": { "braze_h2_firing": { "val": 280, "unit": "°C", "status": "candidate", "source": "S-INDIUM-AUSN", "conditions": "solidus, congruent melting" } } } }, { "g": "BCu-1 (Cu100), 1093-1149 C", "note": "Cu braze filler, recommended brazing window 1093-1149 C", "properties": { "temperature": { "braze_h2_firing": { "val": "1093-1149", "unit": "°C", "status": "candidate", "source": "S-STROPPA", "conditions": "recommended brazing window" } } } }, { "g": "BNi-1, 1066-1204 C", "note": "Ni-Cr-B-Si braze filler, recommended brazing window 1066-1204 C", "properties": { "temperature": { "braze_h2_firing": { "val": "1066-1204", "unit": "°C", "status": "candidate", "source": "S-STROPPA", "conditions": "recommended brazing window" } } } }, { "g": "BAlSi-2 / AL 4343 / AA 4343 / EN AW-4343 / UNS A94343 (Si7.5Al bal), 617-672 C", "note": "Al-Si braze filler, recommended brazing window 617-672 C", "properties": { "temperature": { "braze_h2_firing": { "val": "617-672", "unit": "°C", "status": "candidate", "source": "S-PI-AL4343", "conditions": "recommended brazing window" } }, "thermal": { "cte": { "val": 21.6, "unit": "ppm/K", "status": "candidate", "source": "S-PI-AL4343" } } } }, { "g": "BAu-1 / 37.5Au-62.5Cu (Au37.5Cu62.5), 1016-1093 C", "note": "Au-Cu braze filler, recommended brazing window 1016-1093 C", "properties": { "temperature": { "braze_h2_firing": { "val": "1016-1093", "unit": "°C", "status": "candidate", "source": "S-STROPPA", "conditions": "recommended brazing window" } }, "thermal": { "cte": { "val": 18.8, "unit": "ppm/K", "status": "candidate", "source": "S-WESGO-BAU1", "conditions": "over 20-500 C" } } } }, { "g": "TiCuNi / EP 0238433, 925-945 C", "note": "Ti-Cu-Ni titanium-active braze filler, solidus to liquidus 925-945 C", "properties": { "temperature": { "braze_h2_firing": { "val": "925-945", "unit": "°C", "status": "candidate", "source": "S-EP0238433", "conditions": "solidus to liquidus" } } } }, { "g": "35Au/65Cu (Au35Cu65), 990-1010 C", "note": "Au-Cu braze filler, solidus to liquidus 990-1010 C", "properties": { "temperature": { "braze_h2_firing": { "val": "990-1010", "unit": "°C", "status": "candidate", "source": "S-AWS-BRAZING-HANDBOOK", "conditions": "solidus to liquidus" } } } }, { "g": "BNi-2 / Nicrobraz LM / AMS 4777 (Cr7B3.1Si4.5Fe3Ni bal), 1010-1175 C", "note": "Ni-Cr-B-Si braze filler, recommended brazing window 1010-1175 C", "properties": { "temperature": { "braze_h2_firing": { "val": "1010-1175", "unit": "°C", "status": "candidate", "source": "S-WC-SELECTOR", "conditions": "recommended brazing window" } } } }, { "g": "4047 / BAlSi-4 / AL 104 (Al88Si12), 577-582 C", "note": "Al-Si braze filler, solidus to liquidus 577-582 C", "properties": { "temperature": { "braze_h2_firing": { "val": "577-582", "unit": "°C", "status": "candidate", "source": "S-WP-BRAZELIST", "conditions": "solidus to liquidus" } } } }, { "g": "Cu-TiH2-Ni", "note": "Cu-TiH2-Ni titanium-active braze filler, no melting data read" }, { "g": "Nicusil 3 (Ag71Cu28Ni1)", "note": "Ag-Cu-Ni braze filler, no melting data read" }, { "g": "97Ag-1Cu-2Zr / Ag-1Cu-2Zr (Ag97Cu1Zr2)", "note": "Ag-Cu-Zr titanium-active braze filler, no melting data read" }, { "g": "Ag-31.5Cu-10Pd (Cu31.5Pd10Ag bal)", "note": "Ag-Cu-Pd braze filler, no melting data read" }, { "g": "35Au-62Cu-2Ti-1Ni / 62Cu-35Au-2Ti-1Ni (Au35Cu62Ti2Ni1), 1015-1026 C", "note": "Au-Cu-Ti-Ni titanium-active braze filler, solidus to liquidus 1015-1026 C", "properties": { "temperature": { "braze_h2_firing": { "val": "1015-1026", "unit": "°C", "status": "candidate", "source": "S-SANDIA-NBCU-ALUMINA", "conditions": "solidus to liquidus" } } } }, { "g": "60Zr-25V-15Cb (Zr60V25Nb15)", "note": "Zr-V-Nb titanium-active braze filler, no melting data read" }, { "g": "50Zr-30V-20Cb (Zr50V30Nb20)", "note": "Zr-V-Nb titanium-active braze filler, no melting data read" }, { "g": "56Zr-28V-16Ti (Zr56V28Ti16)", "note": "Zr-V-Ti titanium-active braze filler, no melting data read" }, { "g": "35Nb-65V (Nb35V65)", "note": "Nb-V braze filler, no melting data read" }, { "g": "pure vanadium (V100)", "note": "V braze filler, no melting data read" }, { "g": "50Cu-40Pd-10Ni (Cu50Pd40Ni10)", "note": "Cu-Pd-Ni braze filler, no melting data read" }, { "g": "palladium (Pd100)", "note": "Pd braze filler, no melting data read" }, { "g": "48Ti-48Zr-4Be (Ti48Zr48Be4)", "note": "Ti-Zr-Be titanium-active braze filler, no melting data read" }, { "g": "49Ti-49Cu-2Be (Ti49Cu49Be2)", "note": "Ti-Cu-Be titanium-active braze filler, no melting data read" }, { "g": "13In-27Cu-60Ag (In13Cu27Ag60)", "note": "In-Cu-Ag braze filler, no melting data read" }, { "g": "10Sn-30Cu-60Ag (Sn10Cu30Ag60)", "note": "Sn-Cu-Ag braze filler, no melting data read" }, { "g": "71.5Ti-28.5Ni / Ni/Ti eutectic 28.5:71.5 (Ti71.5Ni28.5)", "note": "Ti-Ni titanium-active braze filler, no melting data read" } ], "displayGrade": "BAg-8", "propertySourceKeys": [ "aws", "tube" ], "properties": { "wet_cleaning": { "recipe": { "val": "both faying surfaces degreased and oxide-free immediately before the cycle; fluxless vacuum brazing needs a chemically clean surface, not a flux", "status": "candidate" }, "forbidden": { "val": "flux in a vacuum braze; fingerprints on the faying surface", "status": "candidate" }, "limit": { "val": "oxide regrowth between cleaning and furnace loading", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 1e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-12, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "silver evaporates in hot service; never use Cd-bearing braze in vacuum", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 600, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": "577-1219 by filler", "unit": "°C", "status": "candidate", "conditions": "derived across the 37 documented braze fillers, solders excluded: lowest solidus BAlSi-2, highest liquidus or window top Palco" }, "metallurgical_limit": { "val": "BAlSi-2 solidus 577 °C to Palco 1219 °C", "status": "candidate", "conditions": "the span of the braze ladder, derived from fillers.json" } }, "thermal": { "thermal_conductivity": { "val": 355, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 380, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.05", "status": "candidate" }, "melting_softening": { "val": "577-1219", "unit": "°C", "status": "candidate", "conditions": "span of the documented fillers" }, "cte": { "val": 19.6, "unit": "ppm/K", "status": "candidate", "source": "S-WESGO-CUSIL", "conditions": "BAg-8, the card displayGrade, over 20-850 C" } }, "mechanical": { "strength": { "val": "joint property", "unit": "MPa", "status": "candidate" }, "density": { "val": 9.9, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "~1.0", "status": "candidate" }, "resistivity": { "val": 2, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "silver tarnishes", "status": "candidate" }, "joining": { "val": "the workhorse after Mo-Mn metallisation; ABA alloys braze ceramics directly", "status": "candidate" }, "process_notes": { "val": "gold-nickel where silver would evaporate", "status": "candidate" }, "availability_cost": { "val": "commodity filler; gold alloys expensive", "status": "candidate" } } } }, { "id": "vacuum-solders", "symbol": "AuSn", "name": "Vacuum and hermetic solders", "family": "joining-consumables", "status": "workhorse", "sectors": [ "quantum", "vacuum-electronics", "space-test" ], "why": "Below brazing temperatures, hermeticity still exists: AuSn eutectic seals quantum and photonic packages fluxless at 280 C, indium alloys join at temperatures optics survive.", "counter": "SnPb and fluxed solders are banned: flux residues and creep; epoxies are not hermetic over years.", "watchouts": "AuSn is brittle: design the joint, do not just wet it.", "essays": [], "sources": [ { "label": "Indium Corporation alloy data", "url": "https://www.indium.com" } ], "grades": [ { "g": "Au80Sn20 eutectic, 280 C", "note": "fluxless hermetic lid seal and die attach" }, { "g": "In52Sn48, 118 C", "note": "gentle joints near aligned optics" }, { "g": "Pure In, 157 C", "note": "cryogenic compliant joints" } ], "displayGrade": "80Au-20Sn", "propertySourceKeys": [ "aws" ], "properties": { "wet_cleaning": { "recipe": { "val": "fluxless reflow under forming gas or vacuum, on gold-plated surfaces; plasma clean immediately before", "status": "candidate" }, "forbidden": { "val": "flux of any kind in a hermetic package", "status": "candidate" }, "limit": { "val": "gold plating thickness, since the tin consumes it", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 5e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-11, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "gold-tin is stable; avoid anything containing Cd, Zn or Pb", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 200, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 250, "unit": "°C", "status": "candidate" }, "braze_h2_firing": { "val": "280 reflow", "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "AuSn eutectic 280 °C", "status": "candidate" } }, "thermal": { "cte": { "val": 16, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 57, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 150, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.1", "status": "candidate" }, "melting_softening": { "val": "280", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "275 tens", "unit": "MPa", "status": "candidate" }, "youngs_modulus": { "val": 68, "unit": "GPa", "status": "candidate" }, "density": { "val": 14.5, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "~1.0", "status": "candidate" }, "resistivity": { "val": 16, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "good", "status": "candidate" }, "joining": { "val": "hermetic die attach and package sealing", "status": "candidate" }, "process_notes": { "val": "the fluxless alternative to SnPb, and the reason it exists", "status": "candidate" }, "availability_cost": { "val": "preforms from specialist suppliers", "status": "candidate" } } } }, { "id": "vacuum-epoxies", "symbol": "Epx", "name": "Vacuum-rated epoxies", "family": "joining-consumables", "status": "workhorse", "sectors": [ "quantum", "big-science", "space-test" ], "why": "The named exceptions to the adhesive ban: leak patching, feedthrough potting, cryogenic bonding, conductive attach. Each grade exists because it passed outgassing screening; nothing else in the glue aisle did.", "counter": "Generic epoxies and CA glues outgas uncharacterized; that is the whole reason the anti-table exists.", "watchouts": "Mind bake ceilings and CTE mismatch at cryo: fillets crack windows.", "essays": [], "sources": [ { "label": "NASA outgassing database", "url": "https://outgassing.nasa.gov" }, { "label": "Henkel and Epoxy Technology datasheets" } ], "grades": [ { "g": "Torr Seal (Hysol 1C)", "note": "the leak-stop and general vacuum epoxy" }, { "g": "Stycast 2850FT", "note": "filled, CTE-matched: the cryogenic potting standard" }, { "g": "Stycast 1266", "note": "unfilled, low viscosity, cryo impregnation" }, { "g": "EPO-TEK H20E", "note": "silver conductive attach" }, { "g": "EPO-TEK H77", "note": "thermal, insulating attach" } ], "displayGrade": "Torr Seal class", "propertySourceKeys": [ "nasa", "ecss" ], "properties": { "wet_cleaning": { "recipe": { "val": "substrates solvent-cleaned and abraded before bonding; the joint itself is never cleaned after", "status": "candidate" }, "forbidden": { "val": "mould release or silicone anywhere near the bond line", "status": "candidate" }, "limit": { "val": "the full cure schedule: an undercured joint outgasses for months", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 1e-7, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "uncured resin is far worse than cured; the cure schedule is the specification", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 120, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 150, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "Tg 60–150 °C by system", "status": "candidate" } }, "thermal": { "cte": { "val": 60, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 0.2, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 1100, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.9", "status": "candidate" } }, "mechanical": { "strength": { "val": "30–70 tens", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "30–70", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "2–5 %", "status": "candidate" }, "youngs_modulus": { "val": 3, "unit": "GPa", "status": "candidate" }, "density": { "val": 1.15, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" }, "resistivity": { "val": ">1e14 Ω·cm", "status": "candidate" }, "dielectric_strength": { "val": "15–20 kV/mm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "moderate", "status": "candidate" }, "joining": { "val": "it is the joint", "status": "candidate" }, "process_notes": { "val": "every joint is an outgassing source and a future leak", "status": "candidate" }, "availability_cost": { "val": "commodity", "status": "candidate" } } } }, { "id": "lubrication-ladder", "symbol": "MoS2", "name": "The vacuum lubrication ladder", "family": "joining-consumables", "status": "workhorse", "sectors": [ "space-test", "big-science", "vacuum-supply", "semiconductor-equipment" ], "why": "Nothing slides for free in vacuum: cold welding is the default. The ladder runs from sputtered dry films through PFPE greases to cryo thermal contact greases, each rung screened for vapor pressure and radiation.", "counter": "Hydrocarbon greases evaporate, migrate, and polymerize under beams: the classic fogged-optic incident.", "watchouts": "PFPE breaks down catalytically on fresh aluminum wear surfaces (Lewis acid attack): dry films there.", "essays": [], "sources": [ { "label": "ECSS space product assurance, lubrication", "url": "https://ecss.nl" }, { "label": "NASA outgassing database", "url": "https://outgassing.nasa.gov" } ], "grades": [ { "g": "Sputtered MoS2, about 1 um", "note": "the spaceflight dry film reference" }, { "g": "Dicronite (WS2)", "note": "thin dry film for threads and mechanisms" }, { "g": "Braycote 601EF / Krytox PFPE", "note": "vacuum greases for bearings and O-rings" }, { "g": "Apiezon L", "note": "room temperature UHV grease, taps and joints" }, { "g": "Apiezon N", "note": "cryogenic thermal contact grease" }, { "g": "Fomblin Z25", "note": "PFPE pump fluid for oxygen and corrosive service" } ], "displayGrade": "sputtered MoS₂", "propertySourceKeys": [ "ecss", "nasa" ], "properties": { "wet_cleaning": { "recipe": { "val": "substrate cleaned and grit-blasted before sputtering; the film is never wet-cleaned", "status": "candidate" }, "forbidden": { "val": "solvents on a burnished film: it lifts; humidity in storage", "status": "candidate" }, "limit": { "val": "MoS₂ performs better in vacuum than in air, and degrades in storage rather than in service", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": "MoS₂ film 1e-10 · PFPE grease 1e-7", "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "PFPE creeps and its fragments show at m/z 69, 119, 131", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": "MoS₂ 300 · PFPE 150", "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "MoS₂ oxidises in humid air, which is why it is stored dry", "status": "candidate" } }, "mechanical": { "strength": { "val": "film", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" }, "density": { "val": 5.06, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" } }, "engineering": { "corrosion": { "val": "MoS₂ oxidises in humid air", "status": "candidate" }, "joining": { "val": "sputtered, burnished or bonded", "status": "candidate" }, "process_notes": { "val": "the ladder: dry film first, solid metal film next, grease last and under protest", "status": "candidate" }, "availability_cost": { "val": "space tribology suppliers", "status": "candidate" } } } }, { "id": "kalrez-ffkm", "symbol": "FFKM", "name": "Perfluoroelastomers (Kalrez, Chemraz)", "family": "polymers-elastomers", "status": "workhorse", "sectors": [ "semiconductor-equipment", "semiconductor-fabs" ], "why": "The seal that survives the plasma: fully fluorinated backbones shrug off O2 and fluorine radicals to 300 C plus, where FKM chars and sheds particles into the chamber.", "counter": "Viton in a plasma tool becomes a particle source and an etch casualty; metal seals cannot do slit valves and doors.", "watchouts": "Price per O-ring is 10 to 100x FKM: specify by position, not by habit.", "essays": [ "The Floor Under the Fab" ], "sources": [ { "label": "DuPont Kalrez semiconductor grade data", "url": "https://www.dupont.com" } ], "grades": [ { "g": "Kalrez 8085", "note": "plasma and particle-critical positions" }, { "g": "Kalrez 9100", "note": "high temperature plasma duty, about 325 C" }, { "g": "Chemraz 615 class", "note": "broad chemical service alternative" } ], "displayGrade": "Kalrez semiconductor grade", "propertySourceKeys": [ "elast", "semi" ], "properties": { "wet_cleaning": { "recipe": { "val": "IPA wipe, air dry, vacuum bake 200 °C before service", "status": "candidate" }, "forbidden": { "val": "as FKM: ketones, and any lubricant on the seal face", "status": "candidate" }, "limit": { "val": "compound-specific: semiconductor grades are qualified as cleaned, so do not improvise", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 1e-7, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "low", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 300, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 300, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "250–325 °C by compound", "status": "candidate" } }, "thermal": { "cte": { "val": 200, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 0.2, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 1100, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.9", "status": "candidate" } }, "mechanical": { "strength": { "val": "12–17 tens", "unit": "MPa", "status": "candidate" }, "tensile": { "val": "12–17", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "150–250 %", "status": "candidate" }, "youngs_modulus": { "val": 0.01, "unit": "GPa", "status": "candidate" }, "hardness": { "val": "70–90 Shore A", "status": "candidate" }, "density": { "val": 2, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" }, "resistivity": { "val": ">1e13 Ω·cm", "status": "candidate" } }, "engineering": { "corrosion": { "val": "essentially universal", "status": "candidate" }, "joining": { "val": "compressed in a groove", "status": "candidate" }, "process_notes": { "val": "check the compound, not the brand", "status": "candidate" }, "availability_cost": { "val": "roughly ten times the price of FKM", "status": "candidate" } } } }, { "id": "black-coatings", "symbol": "Z306", "name": "Vacuum black coatings", "family": "films-getters", "status": "workhorse", "sectors": [ "space-test", "big-science" ], "why": "Emissivity and stray light are materials problems: shroud paints for radiative sinks, foil and anodize blacks for baffles, each certified for outgassing before it earns its darkness.", "counter": "Ordinary black paint becomes the contamination it was meant to simulate away.", "watchouts": "Adhesion at cryo and particle shedding are the qualification tests, not the color.", "essays": [], "sources": [ { "label": "NASA outgassing database", "url": "https://outgassing.nasa.gov" }, { "label": "Acktar coating data", "url": "https://acktar.com" } ], "grades": [ { "g": "Aeroglaze Z306", "note": "the LN2 shroud and spacecraft PU black, E595 compliant with cure", "properties": { "vacuum": { "outgassing_unbaked_10h": { "val": "1e-7", "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": "1e-9", "unit": "mbar·L/s/cm²", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 120, "unit": "°C", "status": "candidate" } } } }, { "g": "Acktar foil blacks", "note": "etched metal blacks: no organics, baffle grade", "properties": { "vacuum": { "outgassing_unbaked_10h": { "val": "1e-10", "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": "5e-13", "unit": "mbar·L/s/cm²", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 350, "unit": "°C", "status": "candidate" } } } }, { "g": "Black anodize (Martin Black class)", "note": "aluminum baffles, watch the sealed-pore water" } ], "displayGrade": "Acktar Fractal Black", "propertySourceKeys": [ "ecss", "nasa" ], "properties": { "wet_cleaning": { "recipe": { "val": "Acktar: solvent wipe only, it is a vacuum-deposited inorganic film. Z306: do not wet-clean, recoat instead", "status": "candidate" }, "forbidden": { "val": "anything abrasive on either; aqueous on Z306", "status": "candidate" }, "limit": { "val": "for a black coating, any cleaning that raises reflectance has failed", "status": "candidate" } }, "vacuum": { "vapor_pressure": { "val": "Z306 is a paint and behaves like one", "status": "candidate" } }, "temperature": { "vacuum_degas": { "val": "as bake", "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "Z306 binder degrades; Acktar is inorganic", "status": "candidate" } }, "thermal": { "cte": { "val": "substrate", "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": "substrate", "unit": "W/m·K", "status": "candidate" }, "emissivity": { "val": "0.90–0.99, which is the point", "status": "candidate" } }, "mechanical": { "strength": { "val": "coating", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" }, "resistivity": { "val": "Acktar available conductive or insulating", "status": "candidate" } }, "engineering": { "corrosion": { "val": "good", "status": "candidate" }, "joining": { "val": "sprayed (Z306) or vacuum deposited (Acktar)", "status": "candidate" }, "process_notes": { "val": "stray light control and thermal emissivity in one layer", "status": "candidate" }, "availability_cost": { "val": "Acktar and space coating suppliers", "status": "candidate" } } } }, { "id": "cfrp-cyanate", "symbol": "CFRP", "name": "CFRP with cyanate ester resins", "family": "carbon-composites", "status": "workhorse", "sectors": [ "space-test" ], "why": "Optical benches and metering structures that fly: carbon fiber stiffness with resins chosen for microcracking resistance and low moisture outgassing, then baked and bagged before TVAC.", "counter": "Epoxy CFRP drinks moisture and exhales it on orbit, distorting the very geometry it was meant to hold.", "watchouts": "Every cut edge is an outgassing surface: seal or bake accordingly.", "essays": [], "sources": [ { "label": "NASA outgassing database", "url": "https://outgassing.nasa.gov" }, { "label": "ECSS space product assurance standards", "url": "https://ecss.nl" } ], "grades": [ { "g": "RS-3 class cyanate ester prepreg", "note": "dimensionally stable optical structures" }, { "g": "EX-1515 class", "note": "low moisture uptake laminates" } ], "displayGrade": "cyanate ester CFRP", "propertySourceKeys": [ "ecss", "nasa" ], "properties": { "wet_cleaning": { "recipe": { "val": "solvent wipe only, then long vacuum bake at 120–150 °C to drive off absorbed water", "status": "candidate" }, "forbidden": { "val": "immersion: the laminate absorbs and holds water for weeks", "status": "candidate" }, "limit": { "val": "TML and CVCM to the space standard, measured not assumed", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": 5e-7, "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": 1e-9, "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "resin volatiles; cyanate ester chosen for low CVCM", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 150, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 200, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "Tg 250 °C cyanate ester; epoxy far lower", "status": "candidate" } }, "thermal": { "cte": { "val": "-0.5 to 2 along fibre", "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": "5–50 along fibre", "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 900, "unit": "J/kg·K", "status": "candidate" }, "emissivity": { "val": "0.9", "status": "candidate" }, "melting_softening": { "val": "no melt", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "600–1500 tens along fibre", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "1–2 %", "status": "candidate" }, "youngs_modulus": { "val": "70–200", "unit": "GPa", "status": "candidate" }, "density": { "val": 1.6, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" }, "resistivity": { "val": "conductive along fibre", "status": "candidate" } }, "engineering": { "corrosion": { "val": "good", "status": "candidate" }, "joining": { "val": "bonded or bolted", "status": "candidate" }, "process_notes": { "val": "moisture uptake dominates the pump-down", "status": "candidate" }, "availability_cost": { "val": "aerospace supply chain", "status": "candidate" } } } }, { "id": "alkali-dispensers", "symbol": "Rb/Cs", "name": "Alkali metal dispensers", "family": "films-getters", "status": "workhorse", "sectors": [ "quantum" ], "why": "Cold atom physics runs on a controlled trickle of Rb or Cs: chromate-plus-reducer dispensers release clean alkali vapor on current command inside sealed cells and MOT chambers.", "counter": "Bulk alkali ampoules flood systems and corrode; getters alone cannot source the species.", "watchouts": "Activation current windows are narrow: overdrive once, contaminate forever.", "essays": [], "sources": [ { "label": "SAES Getters dispenser data", "url": "https://www.saesgetters.com" } ], "grades": [ { "g": "SAES AMD Rb / Cs dispensers", "note": "the standard cold atom source" }, { "g": "Getter-integrated dispensers", "note": "source plus pump in sealed miniature cells" } ], "displayGrade": "SAES dispenser", "propertySourceKeys": [ "saes" ], "properties": { "wet_cleaning": { "recipe": { "val": "never: the dispenser arrives sealed and is installed dry, gloves and dry N₂", "status": "candidate" }, "forbidden": { "val": "moisture and air, which oxidise the charge before you ever use it", "status": "candidate" }, "limit": { "val": "the alkali metal itself; there is no cleaning step", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": "releases by design", "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "the entire function: Rb reaches 1e-7 mbar at 40 °C", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 150, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "activation by resistive heating, 550–800 °C at the dispenser", "status": "candidate" } }, "thermal": { "melting_softening": { "val": "Rb 39, Cs 28", "unit": "°C", "status": "candidate" } }, "mechanical": { "elongation": { "val": "nil", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" } }, "engineering": { "corrosion": { "val": "violently reactive with water", "status": "candidate" }, "joining": { "val": "spot welded to feedthrough pins", "status": "candidate" }, "process_notes": { "val": "the system bake must stay below the release temperature or you waste the charge", "status": "candidate" }, "availability_cost": { "val": "SAES", "status": "candidate" } } } }, { "id": "rebco", "symbol": "REBCO", "name": "REBCO high temperature superconductor tapes", "family": "films-getters", "status": "future", "maturity": "deployed", "sectors": [ "fusion-private", "big-science" ], "why": "The material bet behind compact high-field fusion: (RE)Ba2Cu3O7 coated conductors carry current at 20 K and 20 T, shrinking the tokamak and its vacuum vessel with it.", "counter": "Deployed at machine scale in the SPARC magnet program (VIPER-class cables); pushed by CFS and MIT, with every fusion startup watching tape supply.", "watchouts": "Quench detection and tape cost are the program risks, not the physics.", "essays": [], "sources": [ { "label": "Commonwealth Fusion Systems, magnet program", "url": "https://blog.cfs.energy" } ], "grades": [ { "g": "REBCO coated conductor tape", "note": "Hastelloy substrate, buffered, Cu stabilized" } ], "displayGrade": "REBCO tape", "propertySourceKeys": [ "euro" ], "properties": { "wet_cleaning": { "recipe": { "val": "as delivered; the tape architecture is sealed", "status": "candidate" }, "forbidden": { "val": "moisture: REBCO degrades with water exposure", "status": "candidate" }, "limit": { "val": "insulation and stabiliser compatibility, not the superconductor", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 150, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "Tc 92 K; the tape delaminates under transverse stress", "status": "candidate" } }, "mechanical": { "strength": { "val": "tape, delamination limited", "unit": "MPa", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "type II, Tc 92 K", "status": "candidate" }, "resistivity": { "val": "zero below Tc", "status": "candidate" } }, "engineering": { "corrosion": { "val": "moisture sensitive", "status": "candidate" }, "joining": { "val": "soldered joints", "status": "candidate" }, "process_notes": { "val": "20 T at 20 K is what makes compact fusion arguable", "status": "candidate" }, "availability_cost": { "val": "ramping fast, still constrained", "status": "candidate" } } } }, { "id": "scandate-cathodes", "symbol": "Sc2O3", "name": "Scandate cathodes", "family": "films-getters", "status": "future", "maturity": "lab", "sectors": [ "vacuum-electronics" ], "why": "Scandia-doped tungsten dispensers emit at lower temperature and higher density than B and M types: longer tubes, denser beams, the next rung of the cathode ladder.", "counter": "Reproducibility and life data still maturing; pushed by the vacuum electronics community (IVEC circuit) and mm-wave TWT programs.", "watchouts": "Emission uniformity is the historic failure mode.", "essays": [ "The Names Nobody Cites" ], "sources": [ { "label": "IVEC proceedings, scandate cathode sessions" } ], "grades": [ { "g": "Scandia-doped W dispenser", "note": "lab and pilot tubes" } ], "displayGrade": "Sc₂O₃-doped W", "propertySourceKeys": [ "tube" ], "properties": { "wet_cleaning": { "recipe": { "val": "never: the impregnant is water reactive", "status": "candidate" }, "forbidden": { "val": "moisture and air exposure after activation", "status": "candidate" }, "limit": { "val": "poisoning by oxygen and water, measured in ppm", "status": "candidate" } }, "vacuum": { "vapor_pressure": { "val": "barium and scandium evaporate by design", "status": "candidate" } }, "temperature": { "vacuum_degas": { "val": 1200, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "activation 1100–1200 °C", "status": "candidate" } }, "mechanical": { "elongation": { "val": "nil", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "~1.0", "status": "candidate" } }, "engineering": { "process_notes": { "val": "10 A/cm² at lower temperature than any current cathode", "status": "candidate" }, "availability_cost": { "val": "research and specialist tube makers", "status": "candidate" } } } }, { "id": "v4cr4ti", "symbol": "V-4-4", "name": "Vanadium alloy V-4Cr-4Ti", "family": "steels-superalloys", "status": "future", "maturity": "lab", "sectors": [ "fusion-private" ], "why": "The other low-activation road: vanadium alloys pair with liquid lithium blankets at temperatures RAFM steels cannot hold.", "counter": "Fabrication base and oxygen pickup remain the blockers; pushed by US and Japan fusion materials programs.", "watchouts": "Interstitial oxygen embrittlement governs every process step.", "essays": [], "sources": [ { "label": "EUROfusion and international materials programs", "url": "https://euro-fusion.org" } ], "grades": [ { "g": "V-4Cr-4Ti", "note": "the reference heat chemistry" } ], "displayGrade": "V-4Cr-4Ti", "propertySourceKeys": [ "euro" ], "properties": { "wet_cleaning": { "recipe": { "val": "not established", "status": "candidate" }, "forbidden": { "val": "oxygen pickup during any hot wet process", "status": "candidate" }, "limit": { "val": "interstitial oxygen, which embrittles", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": "insufficient data", "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": "insufficient data", "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "negligible", "status": "candidate" } }, "temperature": { "bake_assembled": { "val": 450, "unit": "°C", "status": "candidate" }, "vacuum_degas": { "val": 1000, "unit": "°C", "status": "candidate" }, "metallurgical_limit": { "val": "recrystallises ~1100 °C", "status": "candidate" } }, "thermal": { "cte": { "val": 9.7, "unit": "ppm/K", "status": "candidate" }, "thermal_conductivity": { "val": 31, "unit": "W/m·K", "status": "candidate" }, "specific_heat": { "val": 490, "unit": "J/kg·K", "status": "candidate" }, "melting_softening": { "val": 1910, "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "300–400 ys", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "20 %", "status": "candidate" }, "youngs_modulus": { "val": 128, "unit": "GPa", "status": "candidate" }, "density": { "val": 6.1, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "~1.0", "status": "candidate" }, "resistivity": { "val": 25, "unit": "µΩ·cm", "status": "candidate" } }, "engineering": { "process_notes": { "val": "low activation for fusion structures", "status": "candidate" }, "availability_cost": { "val": "research", "status": "candidate" } } } }, { "id": "breeder-ceramics", "symbol": "Li4SiO4", "name": "Breeder ceramics and multipliers", "family": "ceramics-glasses", "status": "future", "maturity": "tested", "sectors": [ "fusion-private" ], "why": "Inside the vessel, materials must also make fuel: lithium ceramic pebble beds breed tritium, beryllide pebbles multiply neutrons.", "counter": "Pebble bed mockups irradiated and thermally cycled in EU and Japan programs; pushed by HCPB-class blanket designs.", "watchouts": "Tritium release kinetics and pebble crushing set the design margins.", "essays": [], "sources": [ { "label": "EUROfusion breeding blanket program", "url": "https://euro-fusion.org" } ], "grades": [ { "g": "Li4SiO4 pebbles", "note": "EU reference breeder" }, { "g": "Li2TiO3 pebbles", "note": "Japanese reference, better stability" }, { "g": "Be12Ti beryllide", "note": "multiplier with lower swelling than Be metal" } ], "displayGrade": "Li₄SiO₄ pebbles", "propertySourceKeys": [ "euro" ], "properties": { "wet_cleaning": { "recipe": { "val": "not applicable: hygroscopic and reactive", "status": "candidate" }, "forbidden": { "val": "moisture, absolutely", "status": "candidate" }, "limit": { "val": "tritium release kinetics, not cleanliness", "status": "candidate" } }, "vacuum": { "outgassing_unbaked_10h": { "val": "insufficient data", "unit": "mbar·L/s/cm²", "status": "candidate" }, "outgassing_baked": { "val": "insufficient data", "unit": "mbar·L/s/cm²", "status": "candidate" }, "vapor_pressure": { "val": "lithium loss at high temperature", "status": "candidate" } }, "temperature": { "metallurgical_limit": { "val": "service 300–900 °C", "status": "candidate" } }, "thermal": { "thermal_conductivity": { "val": "~2", "unit": "W/m·K", "status": "candidate" }, "melting_softening": { "val": "1250", "unit": "°C", "status": "candidate" } }, "mechanical": { "strength": { "val": "pebble crush strength", "unit": "MPa", "status": "candidate" }, "elongation": { "val": "nil", "status": "candidate" }, "density": { "val": 2.4, "unit": "g/cm3", "status": "candidate" } }, "electrical_magnetic": { "relative_permeability": { "val": "1.0", "status": "candidate" } }, "engineering": { "corrosion": { "val": "hygroscopic", "status": "candidate" }, "joining": { "val": "pebble bed", "status": "candidate" }, "process_notes": { "val": "breeds the tritium the machine burns", "status": "candidate" }, "availability_cost": { "val": "programme quantities", "status": "candidate" } } } } ] } }