【摘要】 Nd-Fe-B磁体因其超高的剩磁和最大磁能积而广泛应用于永磁电机。由于Nd-Fe-B磁体的热稳定性较差，永磁电机损耗发热造成的温升使磁体性能急剧下降。如何提高烧结Nd-Fe-B磁体热稳定性，拓宽其使用温度范围成为当前研究热点。一方面，可以提高矫顽力、降低矫顽力温度系数以提高高温下抵抗外磁场扰动的能力。对于矫顽力的提高，本文简述了晶粒细化和晶间添加的原理及方法，并从有利元素和扩散方法两方面详述了晶界扩散工艺的研究进展。从优化微观结构和增强主相矫顽力稳定性两方面综述了降低矫顽力温度系数的方法。另一方面，剩磁与永磁电机功率息息相关，因此可以降低其剩磁温度系数来提高高温时的剩磁，以满足高温下永磁电机的转矩和转速需求。为降低剩磁温度系数，通常掺杂适量钴元素，同时本文还调查了重稀土-钴扩散源晶界扩散研究进展中钴的分布特征。此外，考虑到磁体的实际使用，本文还简述了方形度、不可逆磁通损失以及磁体的加工对磁体热稳定性的影响。最后，对烧结Nd-Fe-B磁体热稳定性研究进行了总结和展望。更多还原

【Abstract】 Nd-Fe-B magnets are widely used in permanent magnet motors due to their exceptional remanence and maximum energy products. However,the heat generation arising from permanent magnet motor losses will induce temperature elevation in Nd-Fe-B magnets,thus leading to significant performance degradation of Nd-Fe-B magnets due to their limited thermal stability. Therefore,enhancing the thermal stability of sintered Nd-Fe-B magnets and expanding their operational temperature ranges have emerged as prominent research priorities. On the one hand,enhancing the resistance to external magnetic field perturbations at high temperatures can be achieved through increasing coercivity or decreasing the temperature coefficient of coercivity. In this review,the principles and methods of grain refinement and intergranular addition are briefly reviewed,and the research progress on the grain boundary diffusion process is reviewed in detail from two aspects:elements beneficial to diffusion depths and various diffusion methods. Meanwhile,research progress on reducing the temperature coefficient of coercivity is systematically reviewed from the aspects of optimizing microstructures and enhancing the coercivity stability of the matrix phases. On the other hand,decreasingthecoefficient of remanence of magnets can improve the high-temperature remanence to satisfy the torque and speed requirements of permanent magnet motors,given that the power of permanent magnet motors is closely related to the remanence of Nd-Fe-B magnets. Current strategies for improving the temperature coefficient of remanence predominantly involve Co doping. Recent studies have also introduced HRE-Co diffusion sources in grain boundary diffusion processes. The distribution characteristics of Co are investigated through progress on grain boundary diffusion studies employing HRE-Co diffusion sources. Furthermore,considering the practical applications of magnets,the effects of squareness,irreversible flux loss,and the machining of magnets on the thermal stability of magnets are also briefly reviewed. Finally,the review concludes with a comprehensive summary and forward-looking perspective on the progress on thermal stability enhancement for sintered Nd-Fe-B magnets.更多还原