Misch-metal-iron based magnets

Abstract

The hard magnetic properties of Fe-Mm-B alloys have been studied in melt-spun ribbons and sintered magnets. The as-spun ribbons were magnetically soft and high coercive fields (Hc∼7 kOe) were obtained after a heat treatment at about 700 °C. This caused crystallization of the sample into the Mm2Fe14B phase. The magnetization and Curie temperature of the crystallized samples were found to be 70 emu/g and 250 °C, respectively. The coercive fields of Mm-Fe-B sintered magnets is lower. Small additions of Al and Dy2O3 are found to increase the coercive field in the range of 6–10 kOe.