Kovar as also known as Nilo k, UNS K94610,ASTM F15,Iron Nickel Cobalt,Sealing Alloy,Alloy 12B,Alloy F15,29HK, KV-1,Dilver P0,Vacon 12,FeNi29Co17(Chinese 4J29)etc
NOTE:
A Nickel-Iron-Cobalt, controlled expansion alloy containing 29% Nickel. It’s coefficient of expansion (which decreases with rising temperature to the inflection point), matches the expansion rate of borosilicate glasses and aluminia ceramics. Applications include glass to metal seals in applications requiring high reliability or resistance to thermal shock, ie. high-power transmitting valves, transistor leads and heaters and photography flash bulbs.