Abstract
A reduction and diffusion method (R/D) is used to make a mother alloy of Sm-Fe-N anisotropic magnets. Reduction of 0.5 wt% of samarium content compared to conventional powder increases magnetization. Milling and surface treatment improve the squareness of demagnetization curve, the aging property and the heat resistance quality. Maximum energy product of 292 kJ/m3 is obtained with the powder. High coercive force is maintainable even if the powder is exposed for 300 h in 80°C and 90 %RH. The maximum energy product of 141 kJ/m3 is obtained with an injection molded anisotropic magnet. The aging property estimated by irreversible flux loss is comparable to the conventional MQP-B magnets. The heat resistance temperature (T-5%) at which the initial irreversible flux loss becomes -5% is 125-more than 150°C for Sm-Fe-N magnets and 150-170°C for hybrid magnets.
