Rare-earth cobalt permanent magnet, manufacturing method therefor, and device

A method for manufacturing a rare-earth cobalt permanent magnet, comprising:

• a step (I) of preparing an alloy consisting of, when a rear-earth element including at least Sm is represented by R, 23 to 27 mass % of R, 1.0 to 5.0 mass % of Cu, 18 to 25 mass % of Fe, 1.5 to 3.0 mass % of Zr, and a remainder consisting of Co and unavoidable impurities;
• a pulverizing step (II) of pulverizing the alloy into a powder;
• a pressure-molding step (III) of pressure-molding the powder into a molded body;
• a step (IV) of sintering the molded body at 1,200 to 1,250° C.;
• a step (V) of performing a solution treatment for a sintered molded body;
• a step (VI) of heat-treating the molded body subjected to the solution treatment at 600 to 850° C.;
• a step (VII) of cooling the molded body subjected to a heat treatment to 400° C. or lower at a rate of 0.2 to 10° C./min;
• a step (VIII) of heat-treating the molded body at a temperature that is between 700 to 900° C. and higher than the temperature in the step (VI);
• and
• a step (IX) of cooling the molded body subjected to the heat treatment to 400° C. or lower at a rate of 0.1 to 5° C./min.

A method for manufacturing a rare-earth cobalt permanent magnet, comprising:

• a step (I) of preparing an alloy consisting of, when a rear-earth element including at least Sm is represented by R, 23 to 27 mass % of R, 1.0 to 5.0 mass % of Cu, 18 to 25 mass % of Fe, 1.5 to 3.0 mass % of Zr, and a remainder consisting of Co and unavoidable impurities;
• a pulverizing step (II) of pulverizing the alloy into a powder;
• a pressure-molding step (III) of pressure-molding the powder into a molded body;
• a step (IV) of sintering the molded body at 1,200 to 1,250° C.;
• a step (V) of performing a solution treatment for the sintered molded body;
• a step (VI) of heat-treating the molded body subjected to the solution treatment at 750 to 850° C.;
• a step (VII) of cooling the molded body subjected to the heat treatment to 500 to 600° C. at a rate of 0.5 to 10° C./min, and then isothermally holding the molded body;
• and
• a step (VIII) of rapidly cooling the molded body subjected to the isothermal holding.