Possibility of high-performance Sm2Fe17N3 sintered magnets by low -oxygen powder metallurgy process

Inspired by the previous result that serious coercivity deterioration of Sm2Fe17N3 powder during sintering can be overcame by suppressing surface oxidation of the powder, this study aimed to explore the possibility of high- performance Sm2Fe17N3 sintered magnets by a low-oxygen powder metallurgy process. Jet-milling under a low oxygen atmosphere was used to prepare Sm2Fe17N3 fine powders with a low oxygen content as well as high (BH ) max reaching 42.8 MGOe (341 kJ/m 3 ). All low-oxidized powders were clearly confirmed to be sintered without coercivity deterioration, and powders with appropriate particle sizes were densified to a relative density exceeding 90% by high-pressure current sintering, despite use of a low sintering temperature below the thermal decomposition temperature. However, the sintered magnets showed an unexpected decline in remanence from the powder, which was caused by a decline in saturation magnetization, and as a result, the (BH ) max of the obtained sintered magnets was 24 MGOe (191 kJ/m(3)).