抄録
Fe3B-based Nd-Fe-B permanent magnetic materials containing Co and Mas additives, where M is one of Al, Si, Cu, Ga, Ag, and Au, were prepared in an extremely low-rare-earth concentration range of around 4 atomic percent. The hard magnetic properties develop as a result of a heat treatment of rapidly solidified amorphous ribbons, which produces a metastable nanocrystalline structure consisting of Fe3B and Nd2Fe14B. Use of the additives considerably reduces the crystallite sizes, and consequently, the alloys attain higher coercivity than that obtained in alloys without the additives. Compaction-molded resin-borlded magnets produced from the Nd-Fe-B-Co-M materials have the following magnetic propertise: HcJ=300kA/m-470kA/m, Br=0.7 T-0.9 T, and (BH) max=50 kJ/m3-73 kJ/m3. The typical values of the temperature coefficients of Br and HcJ of the bonded magnets are -0.05%/K and -0.35%/K, respectively, in the 297 K-413 K range.
