边界结构改性对烧结钕铁硼矫顽力的影响

Effect of Grain Edge Region Modification on the Coercivity of Sintered Nd-Fe-B Magnets

对边界结构改性对磁体的显微组织结构和磁性能以及温度特性的影响进行了研究。设计了第一主相磁粉合金成分Nd_(24)Pr_6Co_(1.8)Fe_(61.1)Nb_(0.6)Al_(0.30)Cu_(0.2)B_(1.0),第二边界区结构合金成分Dy_(30)Fe_(68.2)Nb_(0.6)Al_(0.3)Cu_(0.2)B_(1.0),第三晶界相合金成分Nd_(40)Pr_(10)Fe_(47)Cu_(2.0)B_(1.0)。发现边界结构改性可以在基本不影响或者很小影响剩磁的前提下大幅度提高矫顽力。边界结构改性工艺主要是使重稀土元素Dy通过晶界扩散进入到Nd2Fe14B主相晶粒边界区而不是晶粒芯部,在Nd_2Fe_(14)B主相晶粒边界区形成具有高磁晶各向异性场的(Nd,Dy)_2Fe_(14)B壳层结构,从而达到大幅度提高矫顽力的目的。

The effects of grain edge region structure modification on microstructure, magnetic performance and temperature characteristics of sintered Nd-Fe-B magnets were studied. Three kinds of alloy powders were designed on the boasis of chemical composition Nd24Pr6 Co1.8Fe61.1Nb0.6 Al0.30Cu0.2 B1.0for main phase, Dy30 Fe68.2 Nb0.6 Al0.3 Cu0.2 B1.0 for grain edge region and Nd40Pr10 Fe47Cu2.0 B1.0 for grain boundary phase. The results show that modification of grain edge region structure may greatly increase coercivity （Hcj） with little or no effect on residual magnetization（Br）. Process of grain edge region structure modification is mainly the heavy rare earth element Dy diffusing into the grain edge region rather than the core of Nd2Fe14 B main phase. Shell structure of high magnetic anisotropy field is formed in grain edge region, so as to achieve the goal of greatly increasing of the coercivity（ Hcj ）.