Hempel Special Metals

Kovar

Wido Glombitza

Business Unit Manager Medical, Aerospace, Industry

+41 (0)44 823 88 27
Wido Glombitza

Kovar® is a nickel-iron-cobalt alloy with a coefficient of thermal expansion like that of hard glass. Since Kovar Alloy is tough and versatile, while employing extensive quality controls throughout UNS K94610 alloy’s manufacturing process to ensure uniform physical and mechanical properties for ease in deep drawing, stamping and machining are consistently achieved. Furthermore, the coefficient of thermal expansion (CTE) of Kovar® is its most dynamic mechanical property. It's expansion characteristics match both borosilicate (or Pyrex) glasses and alumina ceramics. This alone ensures it is a highly popular controlled expansion alloys for hermetic sealing applications (also known as Glass to Metals Sealing).

Material Data Sheet

ASTMF15
UNSK94610
AMSI-23011 CL1

Main fields of application

Kovar is used for:

  • Hermetic sealing
  • Production of transistors and diodes in the electronic industry
  • Vacuum systems in chemistry and scientific research
  • Electronic tubes (power, microwave, X-Ray)
  • Hybrid circuit casings
  • Oscillator housings
  • Concentrated solar power
  • Scientific instruments

Chemical composition of Kovar

NiCoFeMnSiC
2917Balance0.50.20.04

Mechanical properties of Kovar

PropertyValue
Density g/cm³8.26
Curie Temp°F 815, °C 435
Melting Point°F 2640, °C 1449
Modulus of Elasticity at 20°CMPa 207
Specific HeatJ/g- °C 0.11
Thermal Conductivity at 20°CW/m.k 17.3
Thermal ExpansionW.m-¹°C 0.17
Electrical Resistivitymm²/m 49
Poisson's coefficient0.317

Delivery program

Material is mainly used in bars or as wire. Various dimensions are available upon request.