Patent ID: 9230721
Filing Date: 2016-01-05
CPC Classification: B22F,C22C,H01F

Claim Text:
1. A method of preparing R—Fe—B-based rare earth magnetic powder having improved magnetic properties, the method comprising: coarse grinding rare earth sintered magnet products as a raw material; performing a hydrogenation process in which a ground product obtained through the coarse grinding is charged into a tube furnace, and the tube furnace is then filled with hydrogen and a temperature of the tube furnace is increased; performing a disproportionation process in which the temperature of the tube furnace is further increased in the same hydrogen atmosphere as that of the hydrogenation process; performing a desorption process in which hydrogen is exhausted from an inside of the tube furnace; and performing a recombination process in which hydrogen in the inside of the tube furnace is vacuum exhausted after the desorption process is performed, wherein the recombination process is performed after the desorption process and the disproportionation process and desorption process are repeated one time.