晶间合金化Ga元素对烧结Nd-Fe-B磁性能与显微组织的影响

用晶间合金化方式直接在(NdPr)29.6(FeCuZr)69.2B1.0粉中加入0.3%Ga(质量分数,以下同),磁体的内禀矫顽力从943.5kA/m提高到1181.0kA/m。分别用晶间合金化方式和传统合金化方式在(Nd-PrDy)30.0(FeCuZr)69.0B1.0中加入0.2%Ga,前者的内禀矫顽力达到1224.0kA/m,远高于后者的971.5kA/m。显微组织结构分析表明:用晶间合金化方式加Ga后改善了边界结构,没加Ga时晶粒边界不平直,晶界处缺陷较多;加Ga后晶界平直光滑,Ga主要分布在晶界,而晶内Ga含量极低。

Effect of Ga on magnetic properties and microstructure of Nd-Fe-B sintered magnets prepared by blending method

Effect of Ga addition by blending powder on magnetic properties and microstructure of Nd-Fe-B sintered magnets has been investigated.The intrinsic coercivity increases from 943.5 kA/m for(NdPr)29.6(FeCuZr)69.2B1.0 to 1 181.0 kA/m for(NdPr)29.6(FeCuZr)69.2B1.0 0.3wt% Ga with the same maximum energy product and slight lower remanence.0.2wt% Ga is added to(NdPrDy)30.0(FeCuZr)69.0B1.0 by blending powder and conventional alloying,respectively.The intrinsic coercivity is 1 224.0 kA/m for the former,remarkably higher than 971.5 kA/m for the latter.Microstructure analyses show that the grain boundaries of the magnets with and without Ga addition are substantially different.The grain boundaries of the Ga-free magnet are meandrous and defective.On the other hand,most of the boundaries of Ga-containing magnets by blending powder method are straight and smooth.Ga element dominantly distributes in intergranular region,little within Nd2Fe14B grains.