Magnetic properties and rare earth element diffusion behavior of hot-deformed nanocrystalline dual-main-phase Nd–Ce–Fe–B magnets

ions. Different from the Nd-Fe-B powders, the Ce-Fe-B powders in the magnet are difficult to deform into a platelet-like shape because of the lack of low melting point RE-rich phase due to the precipitation of the 1 : 2 phase. The inter-diffusion behavior between the Nd-rich region and Ce-rich region in the DMP magnets has been investigated by microstructure analysis. The significant diffusion of Nd and Ce into Ce-rich and Nd-rich grain boundary phases, respectively, was demonstrated. At the same time, Ce prefers to stay in the surface layer of Nd-based 2 : 14 : 1 grains, but less Nd diffuses into Ce-based 2 : 14 : 1 grains due to the 1 : 2 phase presented in the Ce-rich region. The modification of the Ce-rich grain boundary phase by Nd diffusion and the distribution of Nd in the Ce-rich 2 : 14 : 1 phase are beneficial for magnetic properties.