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Matched Seals


Matched seals are achieved when the housing and glass are selected to have similar coefficients of thermal expansion (CTE) over the required operating temperature. The seal is typically made by forming a chemical bond between the glass and the oxide created on the metal housing components prior to sealing. The strength of the seal arises from the chemical bond between the materials.

Matched seals are generally strain free glass to metal seals designed to be used at ambient temperature, they are not recommended for temperatures lower than -65°C or higher than 250°C. The matched seal can be used to make a variety of terminals with comparatively few restrictions on the terminal shape whilst still providing a vacuum tight seal and excellent electrical insulation.

AEC are able to design the shell housing to suit a variety of ceramics, metals and other glasses, typically with the housing and contact pin being of Kovar. Other material combinations are possible. For further information please contact our Design Team at the number below.

Material Requirements

  • All materials are chosen by their thermal expansion characteristics relative to the glass used. The goal is to have them match at the critical temperatures of the application.
  • Many components require processing prior to sealing to attain a seal. This extra processing required is the reason this seal type is typically twice the cost of a compression seal.
Click here to see examples of where our seals can be used.
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Willow Technologies Ltd. Unit 3 Borers Yard, Borers Arms Road, Copthorne, West Sussex, RH10 3LH, UK

Tel: +44 (0) 1342 717102, Fax: +44 (0) 1342 717014, Email:

CORPORATE: Solid State Group

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