Method of producing rare earth-cobalt permanent magnet using special cooling rates

摘要

A method of producing a rare earth-coabalt permanent magnet having high coercive force wherein powdery alloy containing rare earth elements and cobalt as principal component is compacted in magnetic field, the resulting green body is sintered at the temperature between 1,000 DEG to 1,200 DEG C, the sintered body is cooled from the above sintering temperature to quenching temperature in the range of 875 DEG +/-50 DEG C at a rate of 7 DEG C/min. or slower rate, and then further cooled successively from the quenching temperatures to room temperature at a rate of 20 DEG C/min. or faster rate.