Kovar alloy

Kovar alloy is a vacuum melted, iron-nickel-cobalt, low expansion alloy available in sheet,plate,rod,bar,tube,pipe,wire,etc.

Kovar alloy

Type Analysis

Element	Min	Max
Carbon	--	0.02
Nickel	--	29.0
Iron	Balance
Silicon	--	0.20
Manganese	--	0.30
Cobalt	--	17.0

Description

Kovar alloy is a vacuum melted, iron-nickel-cobalt, low expansion alloy whose chemical composition is controlled within narrow limits to assure precise uniform thermal expansion properties. Extensive quality controls are employed in the manufacture of this alloy to ensure uniform physical and mechanical properties for ease in deep drawing, stamping and machining.

Applications

Kovar alloy has been used for making hermetic seals with the harder Pyrex glasses and ceramic materials.This alloy has found wide application in power tubes, microwave tubes, transistors and diodes. In intergrated circuits, it has been used for the flat pack and the dual-in-line package.

Magnetic Properties

Kovar alloy is magnetic at all temperatures below the Curie point. Magnetic properties will depend upon heat treatment; the lower the hardness, the higher the permeability values and lower hysteresis loss. Examples of permeability properties are shown in the following chart:

Flux Density	Treatment
	1830°F (999°C)30 min. - FCPermeability	2010°F (1099°C)20 min. - FCPermeability
5001000200050001000012000	100014002000230034003000	1900350058001000082005000

Kovar alloy