KOVAR ALLOY

KOVAR

Type Analysis

Carbon: 0.02Max, Nickel: 29.0Max, Iron: Balance, Silicon: 0.20Max.

Manganese: 0.30Max, Cobalt: 17.0Max.

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 integrated circuits, it has been used for the flat pack and the dual-in-line package.

Physical Properties

Specific gravity.......................................8.36                          

Curie temperature

°F.................................................... 815

°C.................................................... 435

Density                                                                                 lb/cu in............................................... 0.302                              

kg/cu m............................................... 8359                         

Melting Point

°F.................................................. 2640

°C................................................. 1450

Thermal conductivity                                                                    

Btu-in/ft2/hr/°F...................................... 120                               

W/m-K......................................................17.3 

Electrical resistivity

ohm-cir mil/ft......................................... 294

microhm-mm......................................... 490      

Modulus of elasticity

psi x 10(6) ..................................... 20

MPa x 10(3) .................................. 138