KOVAR - alloy K (1.3981)

The lowest CTE Between 20-500 ºC and equal to glass and ceramics.

Created in 1930. This Ni-Co alloy has two typical applications. Between 20-500 °C, KOVAR (alloy K) has the lowest CTE of all alloys or metals. But its CTE is also equal to glass and ceramics. Making it an ideal metal to seal glass metal or ceramic-metal. Many glass sealing systems are built up with KOVAR. 
PHYNICX KOVAR is melted under vacuum. Applicable norm is ASTM F15. Up to larger sizes than usual, the PHYNICX KOVAR has no phase transformation at -196 °C.

The chemical composition of this alloy is:

KOVAR - alloy K (1.3981)

Nickel (Ni): 29%
Cobalt (Co): 17%
Iron (Fe): Balanced

The expansion properties are:

KOVAR - alloy K (1.3981)

30-400°C [x10-6/K]4,6 - 5,2
30-450°C [x10-6/K]5,1 - 5,5

Typical functions in technologies

  • Positioning
  • Tooling
  • Metal to glass sealing
  • Metal to ceramic sealing
  • Malls (composite manufacturing)

Typical industries that apply this material in their technology

  • Medical
  • Military
  • Lighting
  • Optical
  • Electronics
  • Cryogenics

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