METHOD FOR MANUFACTURING R-T-B-BASED PERMANENT MAGNET

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PROBLEM TO BE SOLVED : To provide an R-T-B-based permanent magnet produced by an HDDR method and having good squareness and a high coercive force. SOLUTION : A method for manufacturing an R-T-B-based permanent magnet includes : a process for preparing a powder of an R-T-B-based alloy containing an R2T14B phase (R is a rare earth element containing 50 atom % or more of Nd and/or Pr, and T is Fe, or Fe and Co), in which a 50% volume center particle diameter is 1 μm or larger and smaller than 10 μm; a process for molding the powder to produce a green compact; a first heat treatment process for performing a heat treatment for the green compact in a hydrogen atmosphere at a temperature of 250°C or higher and 600°C or lower; a second heat treatment process for performing the heat treatment for the green compact in the hydrogen atmosphere at a temperature of 650°C or higher and 1000°C or lower; and a third heat treatment process for performing the heat treatment for the green compact in vacuum or an inert atmosphere at a temperature of 650°C or higher and 1000°C or lower. In a period from the end of the first heat treatment process to the start of the second heat treatment process, the temperature rises in vacuum or the inert atmosphere. COPYRIGHT : (C)2013, JPO&INPIT