Nd-Fe-B sintered magnets were heat-treated in Dy vapor atmosphere for achieving (Nd,Dy)-Fe-B magnets by grain boundary diffusion (GBD). The magnetic properties, microstructure, and corrosion resistance of (Nd,Dy)-Fe-B magnets were systematically investigated. Results show that the intrinsic coercivity of magnets increases significantly after Dy diffusion. Dy atoms penetrate into the magnets through the grain boundaries, which not only increase the total amount of rare earth and widen the grain boundary but also form (Nd,Dy)2Fe14B phase with higher anisotropic field on the grain surface layer. The intrinsic coercivity Hcj of (Nd,Dy)-Fe-B magnets increases from 16.86 to 21.60 kOe. When the testing time of highly accelerated aging tester is 96 h, the weight loss of pristine Nd-Fe-B magnets is 0.436 mg/cm2, while that of (Nd,Dy)-Fe-B magnets is 1.922 mg/cm2. The results of weight loss test and potentiodynamic polarization curves show that the corrosion resistance of (Nd,Dy)-Fe-B magnets is worse than that of pristine magnets due to more rare earth amount and wider grain boundary.

中文翻译：

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晶界扩散法获得的(Nd,Dy)磁体的耐腐蚀性能研究


在 Dy 蒸气气氛中对 Nd-Fe-B 烧结磁体进行热处理，通过晶界扩散 (GBD) 获得 (Nd,Dy)-Fe-B 磁体。对(Nd,Dy)-Fe-B磁体的磁性能、微观结构和耐腐蚀性能进行了系统研究。结果表明，Dy扩散后磁体的内禀矫顽力显着增加。 Dy原子通过晶界渗入磁体，不仅增加了稀土总量，加宽了晶界，而且在晶粒表层形成了具有较高各向异性场的(Nd,Dy)2Fe14B相。 (Nd,Dy)-Fe-B磁体的内禀矫顽力Hcj从16.86 kOe增加到21.60 kOe。当高加速老化试验机测试时间为96 h时，原始Nd-Fe-B磁体的失重为0.436 mg/cm2，而(Nd,Dy)-Fe-B磁体的失重为1.922 mg/cm2。失重试验和动电位极化曲线结果表明，由于稀土含量较多、晶界较宽，(Nd,Dy)-Fe-B磁体的耐腐蚀性能比原始磁体差。