| 摘要 |
PURPOSE:To improve the corrosion resistance of a permanent magnet by providing a vapor-phase plating layer on the permanent magnet which mainly contains R (R is at least one of rare earth elements including Y) B and Fe, and tetragonal crystal of main phase and producing a diffused layer between the plating layer and the magnet. CONSTITUTION:Rare earth elements R used for a permanent magnet material of this invention are included in a range of 8-30atom%. If less than 8atom%, high magnetic property and hence high coercive force is not obtained, and if more than 30atom%, its remaining magnetic flux density Br decreases. B is included in a range of 2-28atom%. If less than 2atom%, high coercive force (iHc) is not obtained, and if more than 28atom%, its remaining magnetic flux density Br decreases. Fe is included in a range of 42-90atom%. If less than 42atom%, the remaining magnetic flux density Br decreases, and if more than 90atom%, high coercive force is not obtained. A thin corrosion resistance film is formed by vapor-phase plating layer forming means on the surface of the magnet of the above components. A diffused layer is formed between the plating layer and the magnet, and heat treated at 250 deg.C or age hardening tempera ture or lower. The thickness of the diffused layer is preferably 0.01-10mum by consider ing the corrosion resistance and the sealability with a base magnet. |
