New Sm(Co, Fe, Cu, Zr) magnets with better temperature stability

Abstract A comprehensive and systematic study of the effect of composition and processing on the microstructure and coercivity of Sm(Co, Fe, Cu, Zr)z magnets allowed us to control their temperature coefficient of coercivity all the way from negative to positive values and obtain magnets with the record value coercivity of 10 kOe at 500°C. The Cu content also controls the evolution of microstructure and magnetic properties. In magnets with higher Cu content, a simpler aging cycle, which skips the slow cooling stage from 850°C to 400°C, was found to fabricate magnets with a room temperature coercivity of over 22 kOe and a better temperature dependence of coercivity. The results of this study promise a scientific and technological guideline for the future fabrication of high-performance sintered magnets with an operating temperature of 550°C.