Iron Nickel Cobalt Alloy Kovar 

The expansion characteristics of Kovar match both borosilicate (or Pyrex) glasses and alumina ceramics, making it one of the most popular of the controlled expansion alloys for hermetic sealing applications.    Kovar alloy is a iron-nickel-cobalt, low expansion alloy whose chemical composition is controlled within narrow limits to assure precise uniform thermal expansion properties. Kovar alloy has been used for making hermetic seals with the harder Pyrex glasses and ceramic materials.   Kovar Specification ASTM UNS W.Nr F15 K94610 1.3981    Kovar Chemical composition Grade % Ni Cr Fe Co Cu…