SSC INVAR 36 nickel alloy plate (UNS K93603) is an austenitic nickel-iron alloy containing 36% nickel. It has an extremely low coefficient of thermal expansion from -418°F (-250°C) to 392°F (200°C). The alloy has good fatigue and mechanical properties at cryogenic temperatures.

What is Invar made of?

Invar, alloy of iron that expands very little when heated; it contains 64 percent iron and 36 percent nickel. Invar was formerly used for absolute standards of length measurement and is now used for surveying tapes and in watches and various other temperature-sensitive devices.

What is Kovar material?

Kovar is an iron-nickel-cobalt alloy with a coefficient of thermal expansion similar to that of hard (borosilicate) glass. This makes it especially suitable for uses which require a matched-expansion seal between metal and glass parts.