MG法により作製されたSm2Fe17Nx粉末の磁気特性に及ぼす熱処理条件の影響

概要

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The preparation of Sm2Fe17NX permanent magnetic powder whose grain size is finer than the single magnetic domain size of about 300nm has been tried by mechanical grinding(MG) and the subsequent two-step heat treatment; namely the first one is crystallization treatment and the second one is nitriding treatment. The results obtained are summarized as follows: 1)The specimen obtained by MG(as MGcd specimen) was composed of α-Fe and Sm-Fe amorphous phase, and this MGcd specimen was found to turn into Sm2Fe17 phase after crystallization and Sm2Fe17NX phase after nitriding. 2)Though the grain coarsening was observed after the two-step heat treatment, the grain size was about 50nm which is much finer than single magnetic domain size of 300nm. 3)The remarkable increment of oxygen content in the specimen was observed by the crystallization treatment. However, such an increment of oxygen content was hardly observed by the nitriding treatment. 4)The maximum cocrcivity of 28 kOc was obtained by the following condition;i.c., MG time:108ks, heat treatment:at 1023K for 1.8ks, nitriding treatment : at 723K for 129.6ks and annealing treatment : at 623K for 7.2ks in N2.