This work reports on the effect of the heavy rare earth element Er on Nd-Fe-B magnets by using a simple Er69Fe31 alloy additive, which is much less expensive than Dy and Tb elements. It was found that the corrosion resistance was improved with a minimal reduction in magnetic properties by rationally controlling the Er69Fe31 addition content. The main reason is that Er element partially replaces the Nd element at the edge of the main phase grain to form an (Er,Nd)2Fe14B shell with low HA, which leads to a decrease in coercivity. However, the improvement in the corrosion resistance is mainly due to the Er69Fe31 alloy addition, which slows down the corrosion rate. Simultaneously, an investigation was conducted into the different advantages that target magnets when subjected to diverse heat treatment methodologies. The above findings may lead to the development of applications for other rare earth elements, thereby accelerating the development of low-cost permanent magnets comparable to commercially available sintered Nd-Fe-B magnets.
Keywords: Er69Fe31 alloy; corrosion resistance; magnetic properties; sintered Nd–Fe–B magnet.