非稀土金属及合金化合物改性烧结NdFeB磁体的研究进展

Progress of sintered NdFeB permanent magnets by the diffusion of non-rare earth elements and their alloy compounds

研究发现,烧结钕铁硼(NdFeB)磁体的矫顽力(H_C)、腐蚀性与晶界相成分、微观结构息息相关.传统熔炼添加重稀土元素虽可改善晶界相提高磁体的H_C及抗蚀性,但同时也使添加物均匀地分布于主相,引起稀磁效应并使成本增加.通过晶界添加非稀土物质调控磁体晶界相,可优化晶界相微观结构,提高其电极电位及润湿性,从而在磁体H_C和耐蚀性得以改善的同时,降低磁体中重稀土元素的用量及成本.对近些年晶界添加非稀土金属及合金化合物调控烧结NdFeB晶界相成分、微观结构及其对磁体H_C、抗蚀性影响的部分研究进行了归纳.

It has been found that the coercivity(HC)and corrosivity of sintered NdFeB magnets are closely related to the components and microstructure of their intergranular phase.The traditional smelting NdFeB magnets with adding heavy rare earth elements can modify intergranular phase to improve the HC and corrosion resistance of magnets.However,it makes the additives be homogenously distributed on the main phase,and causes magnetic decrease and cost increase.With the addition of non rare earth materials into grain boundary,the microstructure of intergranular phase as well as its electrochemical potential and wettability can be optimized.As a result,the amount of heavy rare earth elements and cost of magnets could be reduced whilst the HC and corrosion resistance of magnets can be improved.This paper summarized the research on regulating the components and the microstructure of intergranular phase in sintered NdFeB magnets by non rare earth metals and compounds,and its influence on coercivity and corrosion resistance.