The influence of FeTi and NiTi intermetallide additions on high-temperature oxidation of permalloy alloy

Abstract

As a rule powder metallurgy Permalloy alloys are used in production of parts for electronic instruments. For the purpose of controlling the magnetic and electrical properties and also the wear (in the case of production of magnetic heads) and corrosion resistance appropriate additions of metals or such compounds as carbides and oxides are added to the alloy. In this work use of FeTi and NiTi intermetallides produced by reaction sintering of powders of pure metals in a protective atmosphere as alloying additions to Permalloy is recommended. The size of the original powders is less than 100 {mu}m. For reaction sintering at temperature 50{degrees}C above the eutectic temperature in the Ti-TiFe and TiNi-Ni systems was selected. The contents of titanium, iron, and oxygen in the FeTi alloy is 51.9, 45.7, and 2.4 wt.%, respectively, and of titanium, nickel, and oxygen in the NiTi alloy 59.6, 31.9, and 4.6 wt.%. High-temperature oxidation in air up to 1300{degrees}C with a rate of change in temperature of 15{degrees}C of type 78N Permalloy with additions of FeTi and NiTi alloys was investigated with use of methods of differential thermal and differential thermogravimetric analyses on an OD-103 derivatograph under nonisothermal conditions. The reaction products were studiedmore » by x-ray diffraction phase analysis on a DRON-3 instrument in CoK{sub {alpha}}-radiation. Pure 78N alloy powder with a composition of 78.1% Ni + 19.3% Fe (specimen 1) and also with additions of 1% FeTi (specimen 2) and 1% NiTi (specimen 3) were subjected to oxidation.« less