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Metal
Iron
Alloy K (Kovar®) Controlled Expansion Alloy

Alloy K (Kovar®) Controlled Expansion Alloy

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Description

1.3981 (FeNi29Co17) is an iron-nickel-cobalt alloy whose chemical composition is controlled within narrow limits to ensure precise and uniform thermal expansion and mechanical characteristics. These properties make it an ideal alloy for use in high integrity glass-to-metal and ceramic-to-metal seals, particularly where the application requires resistance to thermal shock. It shows the following features and properties:

Uniform thermal expansion characteristics

Related Standards

ASTM F15

Equivalent Materials

This material data has been provided by Matmatch.

"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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All categories

Applications

Manufacturing

Welding

Glass To Metal Seals

Electronics

Semiconductor Devices

Diodes

Transistors

Electronic Tubes

Microelectronics

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Properties

General

Property	Temperature	Value
Density	23.0 °C	8.25 g/cm³ Show Material materials with Density of 8.25 g/cm³

Mechanical

Property	Temperature	Value
Elastic modulus	23.0 °C	139 GPa Show Material materials with Elastic modulus of 139 GPa
Elongation	23.0 °C	30 % Show Material materials with Elongation of 30 %
Hardness, Vickers	23.0 °C	160 [-] Show Material materials with Hardness, Vickers of 160 [-]
Tensile strength	23.0 °C	540 MPa Show Material materials with Tensile strength of 540 MPa
Yield strength	23.0 °C	380 MPa Show Material materials with Yield strength of 380 MPa

Thermal

Property	Temperature	Value
Coefficient of thermal expansion	30.0 °C	4.6E-6 1/K Show Material materials with Coefficient of thermal expansion of 4.6E-6 1/K
	450.0 °C	5.5E-6 1/K Show Material materials with Coefficient of thermal expansion of 5.5E-6 1/K

Melting point		1450 °C Show Material materials with Melting point of 1450 °C
Specific heat capacity	23.0 °C	500 J/(kg·K) Show Material materials with Specific heat capacity of 500 J/(kg·K)
Thermal conductivity	23.0 °C	17 W/(m·K) Show Material materials with Thermal conductivity of 17 W/(m·K)

Chemical properties

Property	Value
Cobalt	17 % Show Material materials with Cobalt of 17 %
Iron	53 % Show Material materials with Iron of 53 %
Nickel	29 % Show Material materials with Nickel of 29 %

Technological properties

Property
Application areas	General: Power and microwave tubes, transistors and diodes, lids and closures in a variety of hybrid electronic circuit packages.

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