PURPOSE: To provide a permanent magnet alloy which has a small change in coercive force with temp. and has high corecive force and max. energy product, by compounding elements to the compsn. expressed by the specific formula and subjecting the mixture to respective treatments of melting, grinding, sintering, solutionizing and aging.
CONSTITUTION: Respective elements are compounded to the compsn. expressed by the formula (Sm 1-x X x )(Co 1-a-b-c Fe a Cu b M c ) z (X:≥1 kinds amoung Tb, Dy, He, Er, Tm, M:≥1 kinds among Ti, Zr, Hf, 0.05≤x≤0.7, 0.05≤a≤0.35, 0.03≤b≤0.15, 0.005≤c≤0.05, 7.0≤z≤8.3). The mixture is formed into an ingot and is ground. The ground powder is press-molded in about 5W15kOe magnetic field and is sintered for about 15minW2hr at about 1,150W1,230°C. The sintered molding is solutionized for about ≥1hr at about 1,100W1,190°C and is subjected to an initial stage of aging for about 1hr at about 750W950°C. The molding is further continuously cooled down to about 450W300°C at about 1W50°C/min cooling rate. These treatments are preferably accomplished in inert, vacuum, nonoxidative and reducing atmospheres.