Coercive force of new Cu-substituted samarium cobalt alloys

It was found that sintered alloys having a composition of approximately z=8 in Sm(Co0.85Fe0.05Cu0.10)z exhibit a high coercive force on the order of 10 kOe, for 5–10-μm average grain size. Magnetization and demagnetization curves showed that the coercive force is controlled by a nucleation process. Attempts were made to achieve a high density without serious grain growth by means of high-pressure isostatic compaction and hot pressing, resulting in 96% of the density and 7-μm average grain size. With this approach, Br=10.3kG, IHc=10.2 kOe, and a maximum energy product of 22.0 MG Oe were achieved.