Matched seals rely on glass and metal combinations with very similar coefficients of thermal expansion to create a oxide bond that results in a hermetic seal. This design produces a stress-free robust seal. Glass-to-metal feedthroughs of this type are capable of withstanding temperatures of up to 400°C.
Compression seals rely on glass and metal combinations that due to the higher coefficient of thermal expansion of the metallic eyelet 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. Glass-to-metal feedthroughs of this type are capable of withstanding temperatures of up to 250°C.
Brazing is the process of joining two or more materials using a metal alloy with a lowermelting point than that of the materials being joined. This is done through a heating process that can vary greatly in temperature, depending upon the materials and alloys involved.
