Grain boundary infiltration in HDDR processed Nd2Fe14B magnets

Ce72Cu28. Moreover, the Fe content in the quaternary Nd-Fe-Ga-Cu system was varied to investigate the effect of grain boundary phase magnetism on the resultant coercivity. The largest coercivity enhancement, from 0.42 T in the as-HDDR powder to 1.88 T after infiltration was observed in the case of ternary Nd80Ga15Cu5 composition. Furthermore, it also shows the best temperature stability with the infiltrated sample still exhibiting a coercivity of 0.58 T at 200 degrees C. Infiltration of light rare earth (La, Ce) based alloy did not increase coercivities due to poor wetting at the grain boundaries. Adding Fe to the grain boundary alloys was shown to enhance magnetization up to a certain extent without significant loss in coercivity. These findings demonstrate the effectiveness of grain boundary infiltration in HDDR-processed magnets without using heavy rare earths. The infiltration with non-magnetic material strongly decreases the intergranular interaction, reflected in a different magnetic domain evolution during the magnetization reversal process.

Automated summary

This study investigates the effect of grain boundary phase magnetism on coercivity in the quaternary Nd-Fe-Ga-Cu system. It is found that adjusting the Ce and Fe content, as well as infiltrating different materials, can effectively enhance the coercivity and temperature stability of magnets. The findings provide a better understanding of the influence of grain boundary phase magnetism on coercivity.