A method of producing a rare earth magnet

文件类型：PDF文档
文件大小：89K
PROBLEM TO BE SOLVED : To reduce the activating time of an alloy till hydrogen absorption, to reduce dispersion in pulverizability therein and to increase the efficiency of the production by subjecting an R-T-B series alloy thin piece to immersing treatment into an acid aq. soln., subjecting it to washing and drying to execute surface modification and thereafter executing hydropulverization. SOLUTION : The alloy raw material for an R-T-B series permanent magnet is produced by subjecting electrolytic iron-ferroboron alloy-rare earth metal to high-frequency melting and rapidly solidifying the alloy molten metal by a single roll metal or a twin roll method. The thin piece of this alloy raw material is subjected to immersing treatment into an acid aq. soln., which is subjected to washing and drying to activate the surface of the alloy. Next, it is housed in an absorbable and exhaustible vessel and is allowed to execute hydrogen absorption under >=0.10 kg/cm hydrogen pressure, and hydropulverization is performed. Since the base and main phase base are exposed on the surface of the alloy subjected to the pickling, the probability that hydrogen molecules adsorb into the alloy base increases, and the activating time, i.e., the hydrogen absorption starting time is reduced. The amt. of hydrogen atoms to be dispersed into the boundaries and grains after the adsorption increases.