Morphology and heat treatment of a Fe60Cr30Co10 magnetic alloy

A Fe60Cr30Co10 alloy heat-treated at temperatures from 500 to 1400 °C has been studied by means of the X-ray phase analysis and transmission electron microscopy. A coercive force has been measured also. It has been shown, that austenite grains observed after water-quenching from temperatures above 800 °C are totally dissolved if the subsequent heat treatment was performed at 700 °C for a short time. It has been noted that the heat and thermo-magnetic treatments in the temperature range from 600 to 660 °C have no effect on both the microstructure and the hard magnetic properties of the alloy. A microstructure characteristic for a high-coercive state is formed during aging at 550 °C, and the high-coercive state, as such, is reached at slow cooling from 550 to 500 °C. The reasons of these transformations have been explained and the tendencies in the development of heat treatment favoring the formation of the high-coercive state have been considered.