| 简介 |
PROBLEM TO BE SOLVED : To obtain raw-material alloy fine powder having low oxygen contents for high magnetic characteristics while easily handling raw-material alloy fine powder (residual powder) remaining in a crushing system. SOLUTION : In a manufacturing method for a rare-earth magnet, raw-material alloy coarse powder is air-current crushed in a closed circuit for the crushing system, and raw-material alloy fine powder is manufactured. In the manufacturing method, raw-material alloy coarse powder is air-current crushed under the state in which an oxygen concentration in the closed circuit is held at a value less than 0.2%, raw-material alloy fine powder is recovered, and the oxygen concentration in the closed circuit is held for a fixed time in 0.8 to 2.0%. The oxygen concentration in the closed circuit is held for the fixed time in 0.8 to 2.0%, and the closed circuit is opened to an atmospheric air. Alternatively, the oxygen concentration in the closed circuit is held for the fixed time in 0.8 to 2.0%, and the next raw-material alloy coarse powder is air-current crushed under the state in which the oxygen concentration in the closed circuit is held in 0.2 to 0.5% without opening the closed circuit to the atmospheric air. COPYRIGHT : (C)2007, JPO&INPIT |
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