METHOD FOR USING RARE EARTH SINTERED MAGNET

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PROBLEM TO BE SOLVED : To provide a method for using an R2Fe14B-based sintered magnet in a motor exposed to a hydrogen atmosphere. SOLUTION : In a rare earth sintered magnet, comprising 20-35 wt.% of R (R is one or more than one kind of rare earth element selected from among Nd, Pr, Dy, Tb and Ho), 15 wt.% or lower of Co, 0.2-8 wt.% of B, 8 wt.% or lower of at least one kind of element selected from among as an additive from Ni, Nb, Al, Ti, Zr, Cr, V, Mn, Mo, Si, Sn, Ga, Cu and Zn, and the remainder of Fe and inevitable impurities, a copper plating layer is formed, as a metal plating layer, on the surface of the rare earth sintered magnet and a nickel plating layer is formed thereon, and the rare earth sintered magnet having a metal oxide layer and/or a metal nitride layer via the metal plating layer is used in a hydrogen atmosphere, under a pressure exceeding 0.1 MPa. An R2Fe14B-based sintered magnet can be used in a motor, even in a hydrogen atmosphere, without causing hydrogen embrittlement. COPYRIGHT : (C)2008, JPO&INPIT