SINTERED SOFT-MAGNETIC MATERIAL EXCELLENT IN WEAR RESISTANCE

PURPOSE:To produce a sintered soft-magnetic material having superior wear resistance by dispersedly incorporating a hard shell-like phase having specific dimensions and composed principally of fine shell-like Al2O3 into a 'Permalloy(R)' and exerting sintering. CONSTITUTION:An Ni-Al alloy powder is subjected to oxidizing treatment by means of high temp. heating in the air and then heated in a hydrogen atmosphere to undergo reduction, then a hard shell-like phase containing Ni-alloy powder where fine alumina coagulated into shell-like state of 5-25mum average outside diameter and 1-10mum thickness is contained inside is prepared. The powders of carbonyl Ni and carbonyl Fe are mixed with the above-mentioned powder and the resulting powder mixture is filled into a metal mold and press- compacted into a green compact, and this green compact is sintered in a hydrogen atmosphere. By this method, the 'Permalloy(R)' type sintered soft-magnetic material having a structure in which the hard shell-like phase composed principally of fine shell-like Al2O3 is distributed by 1-10vol.%, excellent in magnetic properties and wear resistance, and suitable for head core for magnetic recording device can be obtained.