HIP sintering and magnetic properties of Sm2Fe17N3

Sm2Fe17Nx has been hipped to realize the excellent magnetic properties; high Curie temperature, strong uniaxial anisotropy and high saturation magnetization. Sm2Fe17Nx decomposes to SmN and α-Fe at above 600 °C. Sintering of Sm2Fe17Nx is impossible under atmosphere pressure. In this study, HIP sintering and magnetic properties of Sm2Fe17N3 have been studied in terms of the possibility of practical use as a permanent magnetic material. Milled powder of Sm2Fe17N3 was charged into an aluminum capsule applying uniaxial pressure of 50 MPa in nitrogen atmosphere. The hipped Sm2Fe17N3 having 92% of relative density was obtained at 450 °C under 200 MPa without decompition. The relative density obtained was larger than those of bonded magnets. Magnetic field of 4.14 MA/m (52 kOe) was applied to orientate the powder in the capsule. Giving an orientation to the specimen, the maximum magnetic properties were obtained as follows; remanent magnetization: 0.96 T (9.6 kG), and (BH)max: 118 kJ/m3 (14.8 MGOe).