放电等离子烧结NdFeB永磁材料的电化学腐蚀行为研究  

Corrosion Behavior of Spark Plasma Sintering NdFeB Magnets

作　　者：刘卫强[1] 张久兴[1] 岳明[1] 王公平[1] 李涛[2] 

机构地区：[1]北京工业大学 新型功能材料教育部重点实验室,北京100022 [2]北京科技大学 材料科学与工程学院,北京100083

出　　处：《北京工业大学学报》2006年第7期642-646,共5页Journal of Beijing University of Technology

基　　金：国家自然科学基金(50371002;50201001);北京市教委科技发展资助项目(Km20031005019);北京市新星资助项目(2003B03).

摘　　要：利用极化曲线和电化学阻抗谱技术研究了放电烧结NdFeB永磁材料在不同电化学环境下的腐蚀行为及其动力学过程．结果表明：在碱性环境中,磁体的电化学反应受表面电荷传递过程的控制,由于磁体表面形成了一层致密的保护膜,磁体表现出明显的钝化特征；在弱酸性环境中,磁体的电化学反应受表面活性物质吸附过程控制,磁体表面的阳极(富Nd相)区域存在电化学反应的活性通道,磁体因此很容易发生电化学腐蚀；与传统烧结磁体相比,放电等离子烧结磁体具有更好的耐蚀性．Polarization curve and electrochemical impedance spectroscopy （EIS） tests were applied to investigate the corrosion behaviors and corrosion kinetics of spark plasma sintering NdFeB magnets in different electrolytes. The results show that in alkaline solution the electrochemical reaction of the magnets is controlled by the step of surface charge transfer i.e. activation polarization process, the magnet with a compact passivation layer on their surface exhibits evident passive behavior in this circumstance; in weak acid solution, the electrochemical reaction of the magnets is controlled by the step of active substances adsorption process, the magnet is susceptible to corrosion in this environment since there are many active reaction channels in the anodic （Ndrich phase） areas. Compared with conventional sintered NdFeB magnet, SPS NdFeB magnet possesses excellent corrosion resistance.

关 键 词：电化学阻抗谱 放电等离子烧结 NDFEB永磁 钝化 腐蚀 显微组织 极化曲线 

分 类 号：TG178[金属学及工艺—金属表面处理] TM271.3[金属学及工艺—金属学]