GLAZED ALUMINA
High alumina ceramics are impermeable materials which do not normally
require any additional surface treatment to make them suitable for High
Vacuum and Ultra High Vacuum applications. The highest electrical performance
is obtained when using carefully cleaned and dried unglazed alumina.
Surface resistivity under these circumstances is normally 1013
Ohm-cm at ambient temperature.
Glazed alumina components can be supplied, when requested, which
will withstand the metallizing and brazing processes without degradation
of the glaze. Surface resistivity will, however, be that of the glaze
material typically 1012 Ohm-cm at ambient temperature.
The glazed exterior finish acts as a dirt/contamination repellent
and reduces the risk of a 'contamination path' forming across the insulator;
it can also be cleaned more easily than unglazed alumina.
METAL MEMBERS
To ensure maximum integrity and reliability for Ultra High Vacuum applications
only certain metals are employed in the construction of all our products.
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