Sintered rare earth magnet and its manufacturing method

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PROBLEM TO BE SOLVED : To provide a manufacturing method for obtaining a rare earth sintered magnet with Dy and the like efficiently diffused to the inside thereof and with vastly improved coercive force.SOLUTION : The method for manufacturing a rare earth sintered magnet sinters a compact obtained by molding magnet alloy powder containing one or more rare earth elements (R), B, and Fe. The method comprises a diffusion preliminary process where generation energy (E1) of an RFeB type intermetallic compound allows a middle element (Rc) smaller than a main element (Rm) being a rare earth element most contained in the magnet alloy powder and larger than a diffusion element (Rd) being a rare earth element diffused to a sintered body to exist on at least a surface part of the sintered body before diffusion of Rd. Existence of Rc such as Y in the sintered body before diffusion of Rd such as Dy causes deep diffusion of Rd into the inside of the sintered body and then vastly improves coercive force efficiency of the rare earth sintered magnet.