Kovar / 1.3981

Alternative and trade names
Alloy K, Nilo®, Kovar
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Description

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).

Related Standards

Equivalent Materials

This material data has been provided by Hempel Special Metals.

All metrics apply to room temperature unless otherwise stated. SI units used unless otherwise stated.
Equivalent standards are similar to one or more standards provided by the supplier. Some equivalent standards may be stricter whereas others may be outside the bounds of the original standard.

Ashby charts

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Properties

General

PropertyTemperatureValue

Density

23.0 °C

8.26 g/cm³

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Mechanical

PropertyTemperatureValue

Elastic modulus

23.0 °C

207 GPa

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Poisson's ratio

23.0 °C

0.32 [-]

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Thermal

PropertyTemperatureValue

Melting point

1449 °C

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Specific heat capacity

23.0 °C

110 J/(kg·K)

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Thermal conductivity

23.0 °C

17.3 W/(m·K)

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Electrical

PropertyTemperatureValue

Electrical resistivity

23.0 °C

4.9E-7 Ω·m

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Magnetic

PropertyValue

Curie temperature

435 °C

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Chemical properties

PropertyValue

Carbon

0.04 %

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Cobalt

17 %

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Iron

Balance

Manganese

0.5 %

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Nickel

29 %

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Silicon

0.2 %

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Technological properties

Property
Application areas

Kovar is used for:


  • Hermetic sealing
  • Production of transistors and diodes in 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