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Some Physical Properties of Nickel-Iron Alloys

1920; American Institute of Physics; Volume: 16; Issue: 2 Linguagem: Inglês

10.1103/physrev.16.126

1536-6065

L. R. Inǵersoll,

Surface and Thin Film Phenomena

The specific heats, thermal conductivities, thermoelectric powers, and specific resistances have been determined for a series of iron-nickel alloys of exceptional purity and definitely known composition.The specific heat (25\ifmmode^\circ\else\textdegree\fi{} to 100\ifmmode^\circ\else\textdegree\fi{} C.) varies only slightly with change in composition, but gives, nevertheless, a well defined maximum at 35 per cent. nickel. The thermal conductivity (20\ifmmode^\circ\else\textdegree\fi{} to 100\ifmmode^\circ\else\textdegree\fi{} C.) on the other hand, shows a much larger variation. with a value for 35 per cent. nickel of only one fifth of that for either pure iron or pure nickel. The thermoelectric power (o\ifmmode^\circ\else\textdegree\fi{} to 96\ifmmode^\circ\else\textdegree\fi{} C.) against copper exhibits a marked minimum at 35 per cent. nickel with maxima at about 20 per cent. and 50 per cent. The specific resistance at o\ifmmode^\circ\else\textdegree\fi{} C. shows a marked maximum at 35 per cent. nickel, more than five times the value for either pure iron or pure nickel. The relative increase is not so great as the temperature is raised to 700\ifmmode^\circ\else\textdegree\fi{} C. The temperature coefficient of resistance, considering the whole range (o\ifmmode^\circ\else\textdegree\fi{} to 700\ifmmode^\circ\else\textdegree\fi{} C.). is a minimum for the 35 per cent. nickel.These facts are in general agreement with the anomalies in other properties shown by nickel-iron or nickel-steel of this composition and point to the formation of the definite compound ${\mathrm{Fe}}_{2}$Ni.