| 简介 |
PROBLEM TO BE SOLVED : To provide a method for manufacturing a surface-modified rare earth based sintered magnet, wherein, by subjecting the magnet to oxidizing heat treatment, sufficient corrosion resistance is given to it and degradation of its magnetic characteristics is suppressed even under an environment where the temperature or humidity fluctuates, and degradation of the magnetic characteristics resulting from embrittlement of the magnet when it absorbs hydrogen generated under a high-temperature or high-pressure environment is effectively prevented even when the magnet is used for a drive motor of a hybrid or electric vehicle or an IPM motor built-in a compressor of an air-conditioner. SOLUTION : The method includes a step of subjecting heat treatment to a rare earth based sintered magnet under an environment where oxygen partial pressure is 1×102to 1×105Pa and water vapor partial pressure is 200 to 1, 000 Pa and at a temperature of 250 to 600°C, wherein temperature is risen from room temperature to heat treatment starting temperature under an environment where oxygen partial pressure is 1×102to 1×105Pa and water vapor partial pressure is 10-3to 100 Pa by two stages of rising from room temperature to 200°C for below twenty minutes and rising from 200°C to heat treatment starting temperature for twenty minutes or more. COPYRIGHT : (C)2011, JPO&INPIT |
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