Presentation Information
[P1-3]Impact of the RFe2 phase in Ce-containing magnets on annealing optimization and magnetic performance
Fengqiao Liu1, *Yunqiao Wang1, Wei Zhu1, E Niu1, Zhan Wang1, Xiaolei Rao1, Boping Hu1 (1. Beijing Zhong Ke San Huan Research (China))
Keywords:
Ce - containing magnet,RFe2 phase,annealing,Ce/R ratio,transition temperature
Ce - containing magnets have been widely applied in many fields due to their high cost - performance. Compared with Nd magnets, it is well - established that Ce - containing magnets exhibit a greater tendency to form the RFe2 (R = Ce, Nd) phase. This phase exerts a relatively substantial influence on their magnetic properties. Moreover, it impacts the grain - boundary diffusion process. Additionally, owing to the complexity of phase formation, the annealing process for Ce - containing magnets is generally more intricate than that of Nd magnets. This complexity has implications for both the production and application of Ce - containing magnets. Therefore, in this study, we conducted systematic research to reveal the relationships among the evolution of the RFe2 phase, the annealing process, and the magnetic properties.
Ce - containing magnets with different Ce contents (5 - 13%) were annealed at various temperatures. Their magnetic properties were tested, and microstructural observations were carried out using a scanning electron microscope (SEM). Meanwhile, RFe2 (R = Ce, Nd) alloys featuring different Ce/R ratios were fabricated and heat-treated. Subsequently, differential scanning calorimeter (DSC) was employed to determine their phase - transition temperatures. Through the research, we found that within this content range, as the Ce/R ratio increases, the transition point of RFe2 gradually rises. Correspondingly, the optimal heat treatment temperature for Ce - containing magnets also increases. SEM analysis also revealed that as the amount of Ce substitution increases, the area of RFe2 in the magnets after being treated at the optimal heat treatment temperature increases. Moreover, the Ce/R ratio in the RFe2 phase also rises. It is concluded that the Ce/R ratio of RFe2 phase in magnets increases with increasing Ce content, resulting in the variation of transition temperature of RFe2 phase being enhanced simultaneously, which seriously impacts on annealing temperature.
Ce - containing magnets with different Ce contents (5 - 13%) were annealed at various temperatures. Their magnetic properties were tested, and microstructural observations were carried out using a scanning electron microscope (SEM). Meanwhile, RFe2 (R = Ce, Nd) alloys featuring different Ce/R ratios were fabricated and heat-treated. Subsequently, differential scanning calorimeter (DSC) was employed to determine their phase - transition temperatures. Through the research, we found that within this content range, as the Ce/R ratio increases, the transition point of RFe2 gradually rises. Correspondingly, the optimal heat treatment temperature for Ce - containing magnets also increases. SEM analysis also revealed that as the amount of Ce substitution increases, the area of RFe2 in the magnets after being treated at the optimal heat treatment temperature increases. Moreover, the Ce/R ratio in the RFe2 phase also rises. It is concluded that the Ce/R ratio of RFe2 phase in magnets increases with increasing Ce content, resulting in the variation of transition temperature of RFe2 phase being enhanced simultaneously, which seriously impacts on annealing temperature.
