(Ce_(15)Nd_(85))_(30)Fe_(bal)B_1M永磁体湿热条件下的腐蚀性研究

Corrosion Research of(Ce_(15)Nd_(85))_(30)Fe_(bal)B_1M Sintered Magnet in Hydrothermal Environment

研究了双主相的富Ce烧结磁体湿热条件下的腐蚀行为,得到了磁体的显微结构图和失重数据、腐蚀形貌图,同时比对研究了一种性能相近的常用商业N45磁体。结果显示:富Ce烧结磁体的失重比N45磁体的低,腐蚀深度较浅,且腐蚀产物较附着性较好。富Ce烧结磁体的腐蚀机制和N45磁体一样,都是先从富稀土相开始,富Ce烧结磁体腐蚀产物为Fe_2O_3,Fe_3O_4,γ-FeOOH,Nd_2O_3,Ce_2O_3等。富Ce磁体比所选商业N45磁体失重较小的原因是它的晶粒较细小,晶界相均匀分散,腐蚀通道较窄且不连续。所以富Ce烧结磁体可以作为一种新型商业磁体而推广使用,此外,控制富稀土相的分布,减少稀土元素的大量富集及腐蚀通道宽度,是提高磁体耐蚀性能的关键。

The corrosion behavior of Ce-rich sintered magnet was investigated in hydrothermal environment,and microstructure of magnet,and the weight loss and surface topography of corroded magnets were obtained. And a kind of common commercial magnet N45 with properties similar to Ce-rich magnet was comparatively investigated.Results showed that the weight loss of Ce-rich sintered magnet was lower than that of N45 magnet,the corrosion depth was shallower,and the adhesion property of corrosion products was greater. The corrosion mechanism of Cerich sintered magnets and N45 magnets were the same. Corrosion of two kinds of magnets both started from the rare earth phase. The corrosion products of Ce-rich sintered magnet were Fe2O3,Fe3O4,γ-FeOOH,Nd2O3 and Ce2O3,ect. The reason may be summarized as follows： the grain size of Ce-rich magnets was finer than that of Nd Fe B magnets,the grain boundary phase was well dispersed,and the corrosion path was narrow and discontinuous. Therefore,the Ce-rich magnet can be promoted as a new kind of commercial magnet in the future. Besides,the key to improve the anticorrosion of magnet was to try to control the distribution of rare earth phase,reduce the enrichment of rare earth element and corrosion channel width.