Improvement in magnetic properties,corrosion resistance and microstructure of Nd-Fe-B sintered magnets through intergranular addition of Tb68Ni32

• 作者: Jia Li Qingrong Yao Weichao Huang Jue Xie Zhilin Mo Jianqiu Deng Jiang Wang Guanghui Rao Huaiying Zhou
• 来源期刊: 稀土学报（英文版）
• 年，卷（期）: 2022,（5）
• 所属期刊栏目: MAGNETISM AND MAGNETIC MATERIALS
• 页码范围: 784-791
• 页数: 8页
• 语种: 英文

摘要

New energy vehicles and offshore wind power industries have a high demand for sintered Nd-Fe-B magnets with high intrinsic coercivity and high corrosion resistance.In this study,the magnetic prop-erties,anticorrosion properties,and microstructure of Nd-Fe-B sintered magnets with the intergranular addition of low-melting-point eutectic Tb68Ni32 alloy powders were investigated.The aim is to deter-mine if the addition of Tb68Ni32 can improve these properties.A low melting-point eutectic alloy Tb68Ni32 powders was prepared as a grain boundary additive and blended with the master alloy powders prior to sintering.The coercivity of the resultant magnets gradually increases from 1468 to 2151 kA/m by adding increasing amounts of Tb68Ni32.At the same time,the remanence first increases and then slightly decreases.After studying the micro structure and elemental composition of the Tb68Ni32 added magnets,it is found that the significant increase in coercivity and the negligible reduction in remanence is due to densification,improved grain orientation,a uniform and continuous boundary phase distribution,as well as the generation of a(Nd,Pr,Tb)2Fe14B"core-shell"structure surrounding the main-phase grain.Moreover,the corrosion resistance of the magnet is greatly improved owing to the enhancement of electrochemical stability,as well as the optimization of the distribution and morphology of the inter-granular phase.