| 摘要 |
PURPOSE:To produce a rare earth metal-iron-boron magnet contg. a reduced amount of residual calcium by adding calcium to oxides or halides of rare earth metals, subjecting the oxides or halides to reduction and diffusion by heating in the presence of iron and boron and carrying out alloying. CONSTITUTION:Powders of oxides or halides of rare earth metals such as Nd, Pr, Ce and Tb are mixed with powders of iron and boron or oxides of them and powder of calcium or calcium hydride. This powdery mixture is subjected to reduction and diffusion by heating to 950-1,400 deg.C and then alloying is carried out. In the late stage of the reduction or diffusion, the calcium component is removed by vacuum melting and vacuum distillation as required. By this method, a magnet consisting of >=21wt% Fe, <=10wt% B and the balance essentially rare earth metals is obtd. The magnet has a low oxygen content and contains little residual calcium.
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