Materials used for ultrahigh to extremehigh vacuum (10~(-7) approx lO~(-10)Pa) applicationsare described in terms of their vacuum relatedproperties such as outgassing and permeationcharacteristics. Materials discussed here are metals,glasses, ceramics, plastics and elastomers.In order to attain ultrahigh to extremehigh vacuum,outgassing rates must be reduced to the order of 10~(-9)approx 10~(-11) Pam~3/sm~2. Such an order of outgassingrates is usually realized by baking at temperatures 12Oapprox 3OO degC. The effect of baking and surfacemodification on the outgassing rate is given in detailfor major vacuum chamber materials, stainless steels and aluminum alloys.
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