FeNi42 Alloy: Low Thermal Expansion for Precision Seals

1.3917 (FeNi42) is an iron-nickel alloy containing 42% nickel. It exhibits low thermal expansion characteristics over a range of temperatures, which makes it particularly suitable for use in glass and ceramic seals. It finds application in a variety of electronic components and lead frames. It shows the following features and properties:

Low coefficient of thermal expansion matched to silicon, ceramic materials such as alumina and beryllia and vitreous glass compounds

Low thermal expansion characteristics over a range of temperatures

Properties

General

Property	Temperature	Value
Density	23.0 °C	8.15 g/cm³

Mechanical

Property	Temperature	Value
Elastic modulus	23.0 °C	145 GPa
Elongation	23.0 °C	30 %
Hardness, Vickers	23.0 °C	140 [-]
Tensile strength	23.0 °C	500 MPa
Yield strength	23.0 °C	300 MPa

Thermal

Property	Temperature	Value
Coefficient of thermal expansion	30.0 °C	4E-6 1/K
	450.0 °C	7.4E-6 1/K

Melting point		1425 °C
Specific heat capacity	23.0 °C	500 J/(kg·K)
Thermal conductivity	23.0 °C	12.5 W/(m·K)

Chemical properties

Property	Value
Iron	58 %
Manganese	0.8 %
Nickel	41 %

Technological properties

Property
Application areas	It can be found as a sealing material in semiconductor packages, electronic tubes, CRT electron guns, microelectronic components, thermostat rods, vacuum devices and electric industrial lamps

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Metal