烧结钕铁硼磁体腐蚀失重的影响因素及耐蚀性改进

Facters affecting corrosion weight loss of sintered NdFeB magnets and improvement in corrosion resistance

采用粉末冶金法制备系列烧结钕铁硼磁体。采用扫描电子显微镜和电子能谱分析了磁体的微观组织成分,研究了其合金成分(包括Dy含量、Pr含量、稀土总量和微量添加元素)和工艺方法对磁体腐蚀失重影响,并分析了相关机制。实验结果表明,Pr含量、Dy含量以及稀土总量的控制可以改善磁体的失重,改善耐蚀性能。在此基础上通过优化磁体成分和制备工艺,制备出低失重磁体。改善后的磁体失重性能都达到了30天小于3 mg/cm2的水平。通过元素复合添加,提高了磁体磁性能及耐腐蚀性,使其能广泛应用于腐蚀环境。

A series of sintered Nd-Fe-B magnets were prepared via powder metallurgy process.The microstructure and composition of the magnet were analyzed by SEM equipped with EDS,and based on the result,the influences of compositional variation(including Dy,Pr,total rare earth,other supplementary elements)and process on the corrosion induced weight-loss of the magnet were investigated,and the corresponding mechanism was also analyzed.The results show that controlling the contents of Pr,Nd and total rare-rare earths is an effective way to decrease the weight loss and improve the corrosion resistance.Based on the results,a new low weight-loss sintered magnet with optimized component and preparation process was invented,whose weight-loss was lower than 3 mg/cm2 in 30 days.By doping multiple supplementary elements,the magnetic properties and corrosion resistance of the magnet were improved,enabling magnet to be more suitable for corrosive environment.