ArおよびNH3中でのMG処理により作製されたSm2Fe17Nx粉末の窒化過程と磁気特性

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Though the process composed of mechanical alloying, crystallization treatment and nitriding treatment has been used to prepare the Sm2Fe17NX permanent magnet powders with high coercivity, the crystallization treatment increases the oxygen content in the specimen. In this experiment, we tried to prepare the Sm2Fe17NX powders by mechanical grinding(MG) and the nitriding treatment at as low temperature as 623K, where two kinds of powders;i.c., hydrogcnetcd Sm2.5Fe17 powder and non-treated Sm2.5Fe17 powder, were used as the starting materials, and MG was carried out in three kinds of atmosphere ; i.c., in Ar, N2 and NH3 gas. Though the nitriding was promoted by the existence of hydrogen, the oxidation was also promoted. And it was confirmed that too much hydrogen in the specimen impede nitriding. This phenomenon suggests the existence of the most effective concentration of hydrogen for nitriding. In this work, the nitriding was carried out most effectively on the specimen mechanically ground in NH3, where the nitrogen content after nitriding treatment was about 38000ppm.