Coercive Sm2Co17 powder for the bonded magnet application

Microstructure of ingots with nominal composition of Sm(Co0.68Cu0.065FexZry)z, where x = 0.25, 0.27 and 0.30, y = 0.01, 0.02 and 0.03 and z varies from 7.9 to 8.3, were examined at various homogenizing temperatures and magnetic hardening treatments. It was found that the resulting Hci is strongly dependent upon the alloy composition and the homogenizing temperature. In general, the Hci increases as the homogenizing temperature is raised, peaks at a critical temperature, then decreases with increasing homogenizing temperature. This critical temperature may coincide with the solidus curve of the liquid +2:17&rarrTbCu7 type disordered structure transformation. In general, the single phased microstructure achieved after the homogenizing treatment is necessary to obtain the highest Hci after magnetic hardening. For a fixed thermal treatment, the Hci was found to increase with the Zr content.