Patent ID: 7691323

Claim:
A method of manufacturing an anisotropic rare-earth sintered magnet having a maximum energy product (BH) max of at least 25 MGOe, the method comprising heat-treating a Sm 2 Co 17 -based permanent magnet alloy consisting essentially of 20 to 30 wt % of a rare-earth constituent R which is samarium alone or is at least 50 wt % samarium in combination with at least one other rare-earth element, 10 to 45 wt % of iron, 1 to 10 wt % of copper, 0.5 to 5 wt % of zirconium and 0.01 to 1.0 wt % of titanium, with the balance being cobalt and inadvertent impurities, at 1100 to 1250° C. for 0.5 to 20 hours to give the alloy a TbCu 7 -type crystal structure content of at least 50 vol %; milling the magnet alloy; molding the milled alloy to form a compact; sintering the compact; solution-treating the sintered compact; and carrying out aging treatment on the solution-treated compact.