Process for producing permanent magnets and products thereof

摘要: A process for producing permanent magnet materials, which comprises the steps of: forming an alloy powder having a mean particle size of 0.3-80 microns and composed of, in atomic percentage, 8-30% R (provided that is at least one rare earth elements including Y), 2-28% B, balance being Fe inevitable impurities, sintering formed body temperature 900°-1200° C., subjecting sintered to primary heat treatment 750°-1000° then cooling resultant no higher than 680° C. rate 3°-2000° C./min, further thus cooled secondary 480°-700° 35 MGOe, 40 MGOe or energy product can be obtained with specific compositions.