Kovar (Kovar)

Basic Properties

Alloy Type
Designation Kovar
Density 8.36 g/cm³
Melting Point 1450°C

Composition

Element Percentage

Description

Iron-nickel-cobalt alloy with thermal expansion matching glass for glass-to-metal seals.
Density 8.36 g/cm³
Electrical Resistivity 49 μΩ·cm
Tensile Strength 515-620 MPa
Yield Strength 275-380 MPa
Elongation 25-35%
Hardness 160-200 HB
Machinability Good - machines well with standard cutting tools
Melting Point 1450°C
Thermal Conductivity 17 W/(m·K)
Thermal Expansion 5.9 μm/(m·K)
Heat Treatment Stress relief at 480°C, hydrogen annealing for best properties
Heat Treatment Stress relief at 480°C, hydrogen annealing for best properties
Corrosion Resistance Fair - requires protection from corrosion in harsh environments

Applications

Glass-to-metal seals, electronic components, vacuum tubes, hermetic packages, feedthroughs

History

Developed for electronics industry requiring reliable glass-to-metal seals.