Abstract:
Coercivity is a key indicator of the resistance of NdFeB magnets to thermal demagnetization. Sintered NdFeB magnets, due to their relatively low coercivity, face limitations in high-temperature applications. Therefore, enhancing the coercivity of sintered NdFeB has become a focal point of research in the industry. This study aims to elucidate the evolutionary path of coercivity enhancement technologies for sintered NdFeB and predict future trends. Utilizing the Incopat patent database and integrating theories of the technology lifecycle, main path analysis, and SAO semantic analysis methods, we conducted a thorough examination of patents related to coercivity enhancement in sintered NdFeB. The results reveal that the development of coercivity enhancement technologies has undergone a process of “separation—fusion—re-separation,” currently positioned in the maturity phase with significant innovation potential. The evolutionary trajectory has progressed through material and structural modification, process optimization, and industrialization, achieving a balance between improved magnetic performance and cost control. Core technologies are concentrated in the areas of grain refinement, grain boundary doping, and grain boundary diffusion, which enhance coercivity by optimizing grain structure and adjusting boundary composition. Future technological advancements are expected to focus on synergistic enhancements in rare earth permanent magnet technology, improvements in corrosion resistance and high-temperature stability, as well as green manufacturing and sustainable development. This research provides important insights for China’s strategic innovation and positioning in the high-end magnetic materials sector.