LAUSR

Abstract A significant enhancement in coercivity of Nd 7.92 Pr 2.20 Fe 83.91 Zr x B 5.57 Al 0.4−x powders was achieved by Nd 80 Cu 10 Al 10 grain boundary diffusion. The room temperature coercivity was drastically increased from 7.4 kOe to 23.14 kOe by the diffusion process with the content 30% of Nd 80 Cu 10 Al 10 alloy. Nd-Cu-Al alloy diffusion process resulted in grain growth and formed continuous grain boundary phases. The boundary layers were very effective in pinning the motion of domain walls, leading to an increased coercivity. In addition, an increased coercivity was also obtained from 3.1 kOe to 9.8 kOe at 175 °C in the bonded magnets with the diffusion of 30% content NdCuAl alloy. So the thermal stability of the bonded magnets was improved.