PURPOSE: To obtain a permanent magnet of high performance by isothermally treating an alloy lump containing a rare-earth element such as Sm and Co, Fe, Cu, Hf, etc. at a specific temperature.
CONSTITUTION: An alloy lump having the constitution of R(Co1-x-y-zFexCuyMz)A containing an element R, for which Sm or Ce is used mainly, and M, such as Hf, Zr, Ti, Nb, Cr, Mn, Si, etc. and compositions of 0.01≤x≤0.4, 0.02≤y≤0.25, 0.01≤z≤0.15 and 0.5≤A≤0.3 is held for 1 or forty-eight hr at 950W1,200°C, thus removing the segregation of compositions on dissolution, then promoting homogenization. The alloy lump is quenched by water, etc., pulverized and molded in a magnetic field, sintered at 1,160W1,250°C, and quenched. According to said method, an excellent R2CO17 group permanent magnet having coercive force of 103Oe or more and an energy value of 25MGOe or more and superior square molding capability is obtained.
TOKUNAGA MASAAKI
HAGI CHITOSHI
