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. - FC
Permeability
2010°F (1099°C)
20 min. - FC
Permeability
500
1000
2000
5000
10000
12000
1000
1400
2000
2300
3400
3000
1900
3500
5800
10000
8200
5000
