TiZrHfVvalues describe: TiZrHfV
Big science (accelerators, light sources, public fusion)
What it enables
Lower activation temperature than TiZrV: NEG pumping on even less bakeable systems.
Status and pusher
Validated by XPS and pumping tests, baselined for chambers of the HALF light source in Hefei. Pushed by the Chinese light source program on the CERN lineage.
Properties
The values below are candidate: compiled from the sources named, not yet individually validated.
Provisional provenance: CERN vacuum group compilations and coating programme; SAES Getters datasheets and NEG literature.
Wet cleaning
| Recipe | substrate cleaned before coating; the film is never wet-cleaned |
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| Forbidden | venting cycles beyond the qualified count |
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| Limit | activation capacity |
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Vacuum and outgassing
| Outgassing, unbaked (10 h) | pumps |
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| Outgassing, baked | pumps |
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| Vapour pressure | none |
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Temperature
| Bake, assembled | 200 °C |
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| Vacuum degas | 200 °C |
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| Metallurgical limit | activation 150–180 °C, lower than TiZrV |
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Thermal
| CTE | substrate |
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| Thermal conductivity | substrate |
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Mechanical
| Strength | coating |
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| Elongation | nil |
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| Density | ~6 g/cm3 |
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Electrical and magnetic
| Relative permeability | ~1.0 |
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Engineering
| Joining | sputtered in situ |
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| Process notes | the hafnium lowers activation further |
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| Availability and cost | research and pilot installations |
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Sources · 1
- TiZrHfV activation by XPS, NIM-A
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