Nickel Iron Alloys

NiFe 70/30 & NiFe 52/48 - Nickel Iron alloys have been developed to produce high-temperature coefficients of resistance (Positive Temperature Coefficient or PTC) in order to provide a ‘self-limiting’ heating wire.

When the temperature of the wire is around 250 °C the element resistance will have doubled and the power output will have halved.

Improved temperature control

Reduced energy consumption

Reduced power if overheating

High start-up power.

Nickel Iron Alloys are available in sizes down to 0.09 mm.

Physical and Mechanical Properties

UnitsNiFe 70/30NiFe 52/48
Maximum continuous operating temperature in air°C600600
Nominal composition%Ni 70Ni 52
Fe 30Fe 48
Density at 20°Cg/cm³8.458.2
Resistivity at 20°CµΩcm2137
Coefficient of thermal expansion,20 – 100°C1/K15 x 10^610 x 10^6
68 – 212°F1/°F8.3 x 10^65.6 x 10^6
Thermal conductivity at20°CW/mK1717
Specific heat capacity at20°CkJ/kgK0.520.5
Melting point (approx.)°C14301435
Magnetic properties (up to Curie point)MagneticMagnetic
Curie point°C610530
Tensile strength Rm(0.5 mm wire)N/mm²640610
Yield point Rp0.2(0.5 mm wire)N/mm²340340
Elongation at break (approx.) (0.5 mm wire)%3030

Temperature Dependant Factors

Reference temperature 20°C

Temp °C100150200250300350400450500
Temp °F212302392482572662752842932
70/30 Ni/Fe1.351.571.
52/48 Ni/Fe1.331.531.731.932.132.322.492.642.77

The figures given in these tables represent nominal or typical values.

Information contained within this technical data sheet is based upon the general experience of Scott Precision Wire Ltd and is believed to be correct at the time of issue.

No warranty is given or is to be implied from the details above.

Customers are advised to carry out independent tests in order to determine the suitability of any Scott Precision Wire Ltd product for an application.