NdFeB magnets; alloying; coercivity

作者:宋晓平,杨森,王献辉,孙占波,孙军
关键词:rare earths; NdFeB magnets; alloying; coercivity
摘要:Alloying elements Cu and Ti were added to the intergranular regions of sintered NdFeB magnets and their effects magnetic materials
http://www.999magnet.com on microstructure and magnetic properties were investigated. The results show that small amounts 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 grains during sintering. At the same time, 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. As the Ti content increased above 1  2% a strip  like 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 regions is more efficient to modify the properties of NdFeB magnets.