铜、钛复合添加对结NdFeB磁体显微组织和磁性能的影响

研究了烧结NdFeB磁体晶间合添加Cu和Ti 对磁体显微组织和磁性能的影响，当钛含量小于1.2%时，Cu和Ti晶间复合添加可大幅度提高烧结NdFeB磁体的矫顽力，磁变化不大，矫顽力的提高归因于Cu和Ti在主相晶粒表面富集，细化晶粒，阻断主相晶粒之间的磁交换作用，阻碍反磁化畴的传播，当钛含量大于1.2%时，矫顽力略有下降，乘磁急剧下降，乘磁下降的原因在于出现了大量的条状纯钛相。与晶间单独合金化相比，晶间复合合金化可更有效改善NdFeB磁体显微组织与性能。

Effect of Copper and Titanium Addition on Microstructures and Magnetic Propert ies of Sintered NdFeB Magnets

The alloying elements Cu/Ti were added into the intergranular regions of sintered NdFeB magnets, and their effects on microstructure and magnetic properties were investigated. The results show that small amount of Cu/Ti additives can enhance the coercivity greatly and have little effect on the remanence of the magnets, while Ti content is less than 1 2%. The improvement of the coercivity can be attributed to the segregation of Cu and Ti on the surface of main phase, which inhibits the growth of main phase grain during the sintering. At the same time, the segregation of Cu and Ti can also prevent the magnetic coupling of Nd 2Fe 14 B grains to a certain degree and impede effectively the propagation of reversed domain walls through the magnetic phase grains. With the Ti content increasing above 1 2%, a strip Ti rich phase appears in the intergranular region, resulting in the dramatic reduction of the remanence of Nd Fe B magnets. Compared with the single alloying method, the combined alloying of intergranular region is more efficient to modify the properties of NdFeB magnets.