Magnetic Properties of Iron Nitride Foils Prepared by Nitrogen Plasma Irradiation

摘要

We investigated the saturation magnetization andstructure of iron foils treated by nitrogen plasma irradiation. Thesurface of each nitrided foil was removed step by step byelectropolishing, and the saturation magnetization of the nitridedfoil was then measured. X-ray diffraction patterns were takenfrom the electropolished surface at each step. Various ironnitrides were formed at all depths of foils nitrided for 5 hours ormore, and their quantity increased with the nitriding time. Theoutermost region of the surface layer irr-adiated with nitrogenplasma was composed of #gamma#'-Fe_4N and ε- Fe_3N, andthe inner region was composed of #alpha#'-martensite. Thesaturation magnetization of #alpha#'-martensite in a foil nitridedfor 13 hours was 223 emu/g. The nitrogen concentration of#alpha#'-martensite in the foil irradiated with nitrogen plasmawas 0.5 atomic percent.