Nd-Fe-Co-V-Nb-B系交換スプリング磁石の磁気特性

Amorphous melt-spun Nd9Fe74-xCo9V1NbxB7 (x = 0-3) alloy ribbons were prepared by the single-roller melt-spinning method, and the effects of their composition and annealing condition on their magnetic properties were investigated. The optimum condition for preparation of Nd9Fe74-xCo9V1NbxB7 alloy ribbons and some properties are as follows : composition, Nd9Fe73Co9V1Nb1B7; wheel velocity, 15 m/s; annealing condition, 700 °C × 0 min; magnetic properties, (BH)max = 166.4 kJ/m3 (20.9 MGOe). TEM observation showed that the average particle sizes of Nd9Fe73Co9V1Nb1B7 and Nd9Fe71Co9V1Nb3B7 ribbons were about 30 nm and 20 nm, respectively. Fine grains were randomly distributed from spotty rings of electron diffraction. The value of (BH)max for an isotropic compressed bonded magnet prepared by using Nd9Fe73Co9V1Nb1B7 alloy ribbons annealed at 700 °C × 0 min was 96.7 kJ/m3 (12.1 MGOe), and the density was 6.38 Mg/m3.