Tuning Ce distribution for high performanced Nd-Ce-Fe-B sintered magnets

A dual-alloy method was applied to tune the distribution of Ce for enhancing the performance of Nd-Ce-Fe-B sintered magnets with a nominal composition of (Nd0.75Ce0.25)30.5FebalAl0.1Cu0.1B. In comparison to the single alloy of (Nd0.75Ce0.25)30.5FebalAl0.1Cu0.1B, the coercivity was enhanced from 10.3 kOe to 12.1 kOe and the remanence was increased from 13.1 kG to 13.3 kG for the magnets with a dual-alloy method. In addition, the remanence temperature coefficient α and coercivity temperature coefficient β were also slightly improved for the magnet with the dual alloys. The results of microstructure characterizations show the uniform distribution of Ce for the magnet with a single alloy, and the coexistence of the Ce-rich and Ce-lean regions for the magnet with the dual alloys. In combinations with the nucleation of reversal domains and magnetic recoil curves, the property enhancement of magnets with a dual-alloy method was well explained.