| 摘要 |
PURPOSE:To improve an Mn-Sb or Mn-Sb-Bi alloy fine particle permanent magnet in coercive force, oxidation resistance, chemical stability and productivity, by limiting the ratio among Mn, Sb and Bi and the average grain diameter and packing rate of the sintered article made of these alloy fine particles to fall within specific ranges, respectively. CONSTITUTION:The Mn-Sb alloy fine particle magnet should have a composition consisting of 44-52% Sb and the balance substantially Mn by atomic ratio, while the Mn-Sb-Bi alloy fine particle magnet should have a composition consisting of 29-52% Sb, not larger than 15% Bi and the balance substantially Mn by atomic ratio. A slurry obtained by adding an organic solvent or the like to these alloy fine particles having an average grain diameter on the order of 0.1-10thetam is cast. Alternatively, these fine particles or a slurry thereof is pressed or injected and is then pressurized and sintered. The sintering is effected for, e.g., about 0.5-10hr in an atmosphere of an inert gas or the like or in a vacuum at 200-800 deg.C. In this case, the packing rate of the sintered article should be not less than 90%, preferably between 90 and 98%. |
