EFFECT OF COMPOSITION AND MICROSTRUCTURE ON REVERSIBLE LOSSES OF MAGNETIC-PROPERTIES IN FE-ND-B MAGNETS

Temperature characteristics of coercivity and remanence for Fe-Nd-B ma gnets having different compositions and microstructures have been eval uated. Improved performance of a magnet at elevated temperatures can b e achieved by increasing its coercivity. Higher Nd content and a prope r concentration of boron, with combination of additional elements such as Dy, Co or Al increase room and elevated temperature coercivities. High coercivity is also decisive for good temperature characteristics of the remanence. Due to the intrinsic nature of the reversible losses , the relative drop of coercivity is greater for magnets having higher initial coercivity which is mainly related to the phenomena in the ar ea of grain boundaries.