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

AMS I-23011

Equivalent Materials

This material data has been provided by Hempel Special Metals.

"Typical" values were obtained via a literature search. "Predicted" values were imputed via artificial intelligence technology. While we have placed significant efforts in ensuring data accuracy, "typical" and "predicted" data should be considered indicative and verified by appropriate material testing. Please do contact us if additional information on the the predicted data method is required.
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.

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Properties

General

Property	Temperature	Value
Density	23.0 °C	8.26 g/cm³ Show Supplier Material materials with Density of 8.26 g/cm³

Mechanical

Property	Temperature	Value
Elastic modulus	23.0 °C	207 GPa Show Supplier Material materials with Elastic modulus of 207 GPa
Poisson's ratio	23.0 °C	0.32 [-] Show Supplier Material materials with Poisson's ratio of 0.32 [-]

Thermal

Property	Temperature	Value
Melting point		1449 °C Show Supplier Material materials with Melting point of 1449 °C
Specific heat capacity	23.0 °C	110 J/(kg·K) Show Supplier Material materials with Specific heat capacity of 110 J/(kg·K)
Thermal conductivity	23.0 °C	17.3 W/(m·K) Show Supplier Material materials with Thermal conductivity of 17.3 W/(m·K)

Electrical

Property	Temperature	Value
Electrical resistivity	23.0 °C	4.9E-7 Ω·m Show Supplier Material materials with Electrical resistivity of 4.9E-7 Ω·m

Magnetic

Property	Value
Curie temperature	435 °C Show Supplier Material materials with Curie temperature of 435 °C

Chemical properties

Property	Value
Carbon	0.04 % Show Supplier Material materials with Carbon of 0.04 %
Cobalt	17 % Show Supplier Material materials with Cobalt of 17 %
Iron	Balance
Manganese	0.5 % Show Supplier Material materials with Manganese of 0.5 %
Nickel	29 % Show Supplier Material materials with Nickel of 29 %
Silicon	0.2 % Show Supplier Material materials with Silicon of 0.2 %

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