Microstructure, magnetic anisotropy, plastic deformation, and magnetic properties: The role of PrCu in hot deformed CeFeB magnets

Abstract

The usages of high-abundance rare-earth element Ce in the permanent magnet have drawn considerable interest from industrial and scientific societies. In this work, through PrCu addition combined with grain boundary diffusion process (GBDP), anisotropic hot deformed (HD) CeFeB magnets with Jr = 0.66 T, Hci = 514 kA/m, and (BH)max = 55 kJ/m3 can be acquired. The addition of intergranular phase PrCu in spark plasma sintering (SPS) is favorable to the improvement of the plastic deformation ability and the increase of the c-axis crystallographic texture of HDed magnet. Meanwhile, it can also act as a diffusion channel to increase the diffused efficiency during the subsequent GBDP. The observed three Curie temperatures on M-T curves, should be attributed to three various types of 2:14:1 phase, that is initial Ce2Fe14B phase and different (Pr, Ce)2Fe14B phases formed in the process of spark plasma sintering (SPS) and GBDP, respectively. Elemental metallurgical behavior revealed that, the intergranular phases are rich in Pr, Ce, and Cu but depleted in Fe. Intergranular phases analysis demonstrated that, Pr and Ce oxides including (Pr, Ce)O2, Pr12O22, and (Pr, Ce)2O3 can be identified, and amorphous phase is also observed. Through GBDP, magnetic properties, including the coercivity, remanence, and maximum energy product are all improved greatly, which is ascribed to the joint effects from the formation of (Pr, Ce)2Fe14B phase and intergranular phase.