Nickel > Sheet & Strip > Kovar

Kovar is an iron based alloy with nickel and cobalt. The chemistry is closely controlled so as to result in low, uniform, thermal expansion characteristic for the alloy.

Applications: One of the primary uses for this alloy is for glass sealing of metal components, or lead wires, into hard glass or ceramic devices. It also finds use in applications where low expansion with temperature change is a desired characteristic, such as integrated circuits packaging.

Machinability: The alloy is machinable by standard methods.

Forming: Ductility is good and thus forming may be done by conventional methods.

Welding: Welding may be done with any of the conventional methods.

Heat Treatment: See “Annealing”.

Forging: No data. However the alloy is ductile and would be forgeable.

Hot Working: No data. However the alloy would have good hot ductility and could be hot formed.

Cold Working: Readily cold worked by conventional means.

Annealing: Anneal, if necessary, at 2000 F and air cool. Note that annealing after cold working may affect end product thermal expansion characteristics. To restore to original condition in regard to thermal expansion follow the following annealing practice: Anneal in hydrogen atmosphere at 1650 F for one hour. Then raise temperature to 2010 F and hold for 15 minutes followed by cooling to room temperature within one hour.

Hardening: Not applicable.

Other Physical Props: Thermal expansion from Room Temp. to Temperature shown: 212 F 3.25 400 F 2.89 572 F 2.85 750 F 2.81 1100 F 4.34 1300 F 5.06 1475 F 5.73