Research Progress on Grain Boundary Diffusion Sintering of Low-Melting-Point Alloy in Nd-Fe-B Materials

As an innovative technology that emerged in the 21st century, the grain boundary diffusion process (GBDP) enhances the coercivity of sintered Nd-Fe-B magnets through medium and low temperature thermal treatment, enabling heavy rare earth (HRE) elements to diffuse along grain boundaries into the interior of the magnet. This process forms a higher-anisotropy (Nd, HRE) ₂Fe₁₄B phase, optimizes the microstructure and thereby enchances the coercivity of the material. In order to improve the magnetic properties, reduce product costs and the usage of HRE, the development of low melting point alloy diffusion sources has emerged as a significant research focus. This article investigates the mechanism of the alloy diffusion source in enchancing magnet performance and optimizing grain boundary structures, summarizes the current advancements and prospects the future development of alloy diffusion technology.