| 摘要 |
PURPOSE:To improve characteristics and resistance to oxidation of a permanent magnet by carrying out a coating treatment for the permanent magnet with a resin, where such a magnet is obtained by performing a hot pressure formation of mixed powders and pressed green compacts consisting of magnetic powders and non-magnetic metal powders having phases of R2Fe14B as the main phases. CONSTITUTION:The surface of permanent magnet of R2Fe14B-M systems is coated with a resin of resistance to oxidation, where such a magnet is obtained by forming mixed powders or their green compacts under hot pressure at the temperature range 300-1100 deg.C: among the mixed powders, one of which is synthetic powders comprising the following distribution ratios shown by an stomic percentage; 10-20% R (R represents a rare earth element containing Y), 5-15% B as well as Fe ratios composed of remaining percentages and the other of which is powders of non-magnetic elements M having percentages shown by volume distribution ratios; 0-10% (0 is excl.). In such a case, M indicates a sort or two sorts or more of elements such as Zn, Al, S, In, Ga, Ge, Sn, Te, Cu, and Pb or compounds among these elements, alloys of the above and rare earth elements as well as alloys of the above elements and B. Thus the magnet improves its resistance to oxidation by decreasing R-rich phases in the magnet and coating products with the resin holding eminent resistance to oxidation. |
