PURPOSE: To produce a permanent magnet having a small change in coercive force with temp. by limiting the compsn. of intermetallic compds. of rare earth cobalt contg. Fe, Cu and Zr and heat treating the same under suitable conditions after grinding and molding.
CONSTITUTION: The intermetallic compds. of rare earth and cobalt having a compsn. expressed by R(Co1-x-y-zFexCuyMz)A (where R is a combination of ≥1 kind of rare earth elements consisting mainly of Sm, Ce; M is a combination of ≥1 kind of Zr, Nb, Hf, Ti, Ta, Mn, and 0.01≤x≤0.40, 0.02≤y≤0.25, 0.001≤z≤ 0.15, 6.0≤A≤8.3) are ground and molded. After such molding is subjected to solution beat-treatment at ≥1,000°C sintering temp., the molding is cooled quickly and in succession the molding is cooled slowly down to 400°C from a 700W 900°C temp. range at 0.05W10°C/min, and is heated and held for 0.5W10hr at 500W700°C, whereby the permanent magnet having 0.07W0.14%/°C temp. change of coercive force at -50W300°C is produced.
OOMORI TAKEO
ISHIHARA KINYA
