| 摘要 |
PURPOSE:To produce a rare earth cobalt permanent magnet having improved magnetic performance by heat treating an ingot of a casting alloy cosisting of a specific ratio of a rare earth element and a transition metal, crushing the ingot, molding the crushed alloy to a required shape in a magnetic field and sintering the molding. CONSTITUTION:A casting alloy of R2TM17 consisting of a rare earth element R and a transistion metal TM is subjected to a heat treatment, such as a solubilizing treatment and/or precipitation hardening treatment in the state of the ingot. The solubilizing treatment is accomplished by heating the alloy for about 1-100hr at about 1,000- 1,200 deg.C in an Ar atmosphere, and cooling quickly the same at about 10-100 deg.C. The precipitation hardening treatment is accomplished by heating the alloy for about 1- 50hr at about 600-900 deg.C in an Ar atmosphere then cooling quickly the same. The treated alloy is crushed to about 10-2,000mu and is molded under about 0.5-2ton/cm<2> pressure in a magnetic field of about 10-20kG. The molding is further sintered for about 10-60min at about 1,000-1,500 deg.C in a reduced Ar atmosphere of about 300- 100Torr and is quickly cooled. The cooled alloy is further subjected to the solubilizing treatment and precipitation hardening treatment. The treated alloy is processed and magnetized, whereby a rare earth cobalt permanent magnet is produced. |
