Sm2Fe17Nx化合物の保磁力に対する熱処理とMA条件の影響

概要

論文の詳細を見る
Mechanical alloying (MA) of elemental Sm and Fe powders in a laboratory ball mill was conducted to prepare Sm2Fe17Nxpermanent magnet. MA resulted in the formation of an amorphous phase with α-Fe in a wide composition range of Sm-Fe binary system. A single Sm2Fe17 phase was obtained after the subsequent heating of MA powder of the nominal composition of Sm15Fe85. The MA powder of Sm15Fe85 milled for 360ks was heated at various temperatures in the range 973-1073K and nitrided in an atmosphere of purified N2 gas flow for various times in the range of 0.3-21.6ks at 703K. It was observed that coercivity depends on both the heating temperature and nitriding time. When the MA powder was nitrided at 703K for 3.6ks, coercivity was observed to be higher as the heating temperature is lower. The coercivity showed a peak with nitriding time and the peak coercivity was obtained with shorter nitriding time as the heating temperature is lower. The effect of MA time on coercivity was studied under the condition of heating temperature 973K and nitriding at 703K for 3.6ks. The coercivity showed a peak with MA time and the largest coercivity was obtained at around 1080ks of MA. The dependence of coercivity on the heating temperature, nitriding condition and MA time was discussed in relation with the powder particle size and the crystal grain size of MA powder.