Relationship between Hydrogen Pressure and Temperature for Recombination Reactions in the HDDR Processing of Ce-Fe-B Alloys.

In recent years, to reduce manufacturing costs and alleviate the rare-earth supply/demand imbalance in the N-Fe-B magnet market, researchers have actively pursued the development of (Nd,Ce)-Fe-B magnets, in which Nd is replaced by Ce. In the present study, we focused on magnetic powders treated by the hydrogenation-disproportionation-desorption-recombination (HDDR) process and explored the relationship between the hydrogen pressure and temperature (P_H2-T curves) in the Ce-Fe-B system, which is essential for the development of (Nd,Ce)-Fe-B magnets. It was confirmed that the disproportionation and recombination reactions of both Ce₂Fe₁₄B and CeFe₂ take place in the Ce-Fe-B system. Furthermore, compared with Nd₂Fe₁₄B, the P_H2-T curve of Ce₂Fe₁₄B was found to be shifted to higher pressure and lower temperature, suggesting a corresponding shift in the HDDR conditions under which good magnetic properties can be obtained. [ABSTRACT FROM AUTHOR]