不同成分钕铁硼永磁体腐蚀性能的研究

Study on Corrosion Performance of Neodymium Iron Boron Permanent Magnets with Different Compositions

评价了不同成分的NdFeB永磁体的腐蚀性能,探究合金化元素对NdFeB永磁材料腐蚀性能的影响机理。利用高压加速(HAST)和中性盐雾试验腐蚀环境评价了两种不同成分钕铁硼磁体耐腐蚀特性。实验结果表明,重稀土Dy含量、Co含量及Nb含量较高的磁体A的耐腐蚀性能优于重稀土Dy含量、Co含量及Nb含量较低的磁体B。极化曲线测试结果表明,重稀土Dy含量、Co含量及Nb含量较高的磁体A样品要比B样品的自腐蚀电位要高。钕铁硼磁体的耐腐蚀性能随着Dy、Co、Nb等添加元素含量增加而明显改善。Dy、Co、Nb含量高的磁体的自腐蚀电位较高,改善磁体抗腐蚀性能。Dy、Co、Nb更易于分布于晶界相中,降低了晶界上富Nd相的比例,降低了晶界相的化学活性,有效提高了磁体的耐蚀性能。

The corrosion performance of NdFeB permanent magnets with different compositions was investigated,and the influence mechanism of alloying elements on the corrosion performance of NdFeB permanent magnet materials was explored.The corrosion resistance of Nd-Fe-B magnets with two different components was evaluated by using high-pressure accelerated test(HAST)and neutral salt spray test.The corrosion resistance was significantly improved with contents of Dy,Co,Nb increasing.The free corrosion potential of NdFeB magnets with high content of Dy,Co and Nb was higher than that with low content of Dy,Co and Nb.Dy,Co and Nb were more easily distributed in the grain boundary phase,and the proportion of Nd rich phases was reduced on the grain boundary.As a result,the chemical activity of the grain boundary phase could be reduced.