Matched seals rely on glass and metal combinations with similar coefficients of thermal expansion to form an oxide bond that results in a hermetic seal. This design produces a stress free robust seal well suited to many applications.
Compression seals rely on glass and metal combinations that due to the greater coefficient of thermal expansion of the metallic case will create a mechanical bond that provides the hermetic seal. This design is well suited when the design parameters of the final package fall outside of the matched seal glass and metal combinations.
AMETEK does have HTCC capability in-house with relocation of General Ceramics to New Bedford. We have assembled tens of thousands of hermetic packages that included ceramic terminals and/or ceramic feedthrus. Refer to our High Temperature Cofired Ceramic Design Guide.
AMETEK offers 94% min. Al2O3 ceramic seals as an alternative to glass. Some considerations to keep in mind during design stages are:
- Ceramic OD >= lead diameter
- Pin-to-pin spacing – Ceramic OD >= .020”
- Distance from top of ceramic seal to seal ring >= .020”
- Ceramic seals can be brazed into ASTM F-15 Alloy, Copper, CRS or Stainless Steel frames.
- Copper Cored 52 Alloy or GlidCop can be used for the pin material.