Nd-Fe-Co-B-V圧縮成形ボンド磁石の磁気余効

抄録

Compression bonded magnets were manufactured using melt-spun ribbons of Nd₁₁Fe₇₂Co₈B_7.5V_1.5, MQP-B and MQP-D (GM Co., Ltd.). The magnetic field and temperature dependences of the magnetic aftereffect constant (S_V) which decided the magnetic stability, were studied. Compared with the bonded magnets using MQ powders, Nd₁₁Fe₇₂Co₈B_7.5V_1.5 bonded magnet had larger (BH)_max, but smaller S_V (2.3 kA/m). The temperature dependence of S_V for Nd₁₁Fe₇₂Co₈B_7.5V_1.5 bonded magnet was better than that of Nd-Fe-B sintered magnets. The activation volume (v) at room temperature, of Nd-Fe-Co-B-V, MQP-B and MQP-D bonded magnets was approximately 18×10^-25, 15×10^-25 and 18×10^-25 m³, respectively. The relation among H_cJ, S_V and v, namely, Barbier plot, was studied for these Nd-Fe-B system compression bonded magnets, as well as for Sm₂Co₁₇ sintered magnets and Sm₂Co₁₇ system compression bonded magnet whose mechanism of magnetization reversal are the same pinning-type. From the results of Barbier plots, it was found that the relation between In S_V and In H_cJ was straight line, and H_cJ was in proportion to v^-0.6.