Corrosion behaviors of NdFeB magnets prepared by spark plasma sintering

Tao Li, Ming Yue, Aizhi Sun, Baoqin Qiu, Yaofu Xiao, and Jiuxing Zhang Materials Science and Engineering School, University of Science and Technology Beijing, Beijing 100083, China Advanced Functional Materials Key laboratory of the Ministry of Education, Beijing Polytechnic University, Beijing 100022, China

摘 要：<正> The spark plasma sintering （SPS） technique was introduced into the field of NdFeB preparation due to its own advantages. High property NdFeB magnets with fine grains were prepared by SPS method. The corrosion behaviors of SPS NdFeB were studied by electrochemical measurements and 92% RH hyther tests at 353 K. The results were compared with those of the traditional sintered NdFeB magnets. It shows that both the SPS NdFeB and the traditional sintered NdFeB have good corrosion resistance in alkaline environment due to surface passivation; while, the fine grain microstructure of SPS NdFeB results in a more homogeneous phase composition distribution and thus reduces the electrochemical inhomogenity between the ferromagnetic phase and the Nd-rich inter-granular phase in the magnet. Therefore, the SPS NdFeB exhibits better corrosion resistance than the traditional sintered NdFeB in neutral and weak acidic environment.

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