Nickel Kovar (tm)

Annealing Procedure

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.

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.

Cold Workability

Readily cold worked by conventional means.

Forgeability

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

Formability

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

Hardening Procedure

Not applicable.

Heat Treatability

See "Annealing".

Hot Workability

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

Machinability

The alloy is machinable by standard methods.

Other Physical Properties

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

Principle Design Features

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.

Weldability

Welding may be done with any of the conventional methods.