Abstract
Compression bonded magnets were manufactured using melt-spun ribbons of Nd11Fe72Co8B7.5V1.5, MQP-B and MQP-D (GM Co., Ltd.). The magnetic field and temperature dependences of the magnetic aftereffect constant (SV) which decided the magnetic stability, were studied. Compared with the bonded magnets using MQ powders, Nd11Fe72Co8B7.5V1.5 bonded magnet had larger (BH)max, but smaller SV (2.3 kA/m). The temperature dependence of SV for Nd11Fe72Co8B7.5V1.5 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 HcJ, SV 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 SV and In HcJ was straight line, and HcJ was in proportion to v-0.6.
