抄録
Experiments were carried out to investigate the effect of composition, heat-treatment and nitrogenation conditions on the magnetic properties of Sm-Fe-Co-Cr-N compounds with TbCu7-type structure. The optimum preparation conditions of the compounds were as follows: composition: {Sm10(Fe0.9Co0.1)89.7Cr0.3}84.4N15.6, roller velocity: 50 m/s, heat treatment: 700°C for 60 min in high-purity Ar gas, and nitrogenation condition: 420°C for 10 h in high-purity N2 gas. Typical magnetic properties of the obtained compound powders were as follows: Jr = 0.99 T, HcJ = 756.5 kA/m, HcB = 541.8 kA/m, (BH)max = 141.8 kJ/m3 (17.8 MGOe), and Tc = 517°C. It was found that this sample was an exchange spring magnet from recoil loops of the hysteresis curve and X-ray diffraction patterns. The value of (BH)max for the compression-molding isotropic bonded magnet prepared by using {Sm10(Fe0.9Co0.1)89.7Cr0.3}84.4N15.6 powder was 102.6 kJ/m3 (12.9 MGOe), when the density of bonded magnet was 5.98 Mg/m3. And the average reversible temperature coefficient of Jr was α(Jr)ave. = -0.06%/°C, the temperature coefficient of HcJ in the range from 25°C to 125°C obtained by a linear extrapolation was α(HcJ) = -0.41%/°C.
