| 简介 |
PROBLEM TO BE SOLVED : To provide an R-T-B-C rare earth sintered magnet having high magnetic characteristic, by suppressing the heat generated due to eddy current and reduced loss in a fluctuating magnetic field.
SOLUTION : The R-T-B-C rare earth sintered magnet can be obtained, by blending an alloy for R-T-B-C magnet with R-rich R-T-B-C (R denotes Ce, Pr, Nd Tb or Dy and T denotes Fe) and pulverizing, molding and sintering the blended product. The sintered body constitution is made of R2T14B type main phase crystals and a grain boundary phase, and the grain boundary phase is formed of a compound phase, consisting of 40-98 vol.% R-O1-x-F1+2x and or/R-Fy, 1-50 vol.% R-O, R-O-C or R-C compound, an R-T phase, B-rich phase (R1+εFe4B4) or M-B2 phase (M is Ti, V, Cr, Zr, Nb, Mo, Hf Ta or W) and the balance of R-rich phase. As a result, the magnet has a high coercive force and a specified electrical resistance so high that the generation of an eddy current can be suppressed in a utilization environment, where it is exposed to an alternate magnetic field, such as of a motor; and further, the temperature coefficient of the specified electrical resistance is large.
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