烧结NdFeB磁体表层Co/Cu合金化的制备及耐腐蚀性能  

Preparation and corrosion resistance of Co/Cu alloying layer on sintered NdFeB magnets surface

作　　者：沈子函 冉仁豪 张鹏杰 汪冬梅[1,3] 崔接武[1,3] 斯佳佳 徐光青[1,3] 吕珺[1,3] SHEN Zi-han;RAN Ren-hao;ZHANG Peng-jie;WANG Dong-mei;CUI Jie-wu;SI Jia-jia;XU Guang-qing;LÜJun(School of Materials Science and Engineering,Hefei University of Technology,Hefei 230009,China;BGRIMM Magnetic Materials and Technology Co Ltd,Beijing 102600,China;Key Laboratory of Advanced Functional Materials and Devices of Anhui Province,Engineering Research Center of High Performance Copper Alloy Materials and Processing,Ministry of Education,National-Local Joint Engineering Research Center of Nonferrous Metals and Processing Technology,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]合肥工业大学材料科学与工程学院,安徽合肥230009 [2]北矿磁材科技有限公司,北京102600 [3]合肥工业大学,先进功能材料与器件安徽省重点实验室,高性能铜合金材料及成形加工教育部工程研究中心,有色金属与加工技术国家地方联合工程研究中心,安徽合肥230009

出　　处：《材料热处理学报》2025年第1期132-142,共11页Transactions of Materials and Heat Treatment

基　　金：国家重点研发计划项目(2022YFB3504800)。

摘　　要：针对NdFeB磁体本征耐蚀性差的问题,通过磁控溅射结合真空扩散处理,在NdFeB磁体表层制备了Co/Cu合金化层。采用X射线衍射仪和扫描电镜分析表层合金化磁体的物相、成分和形貌。采用动电位极化、交流阻抗谱和静态全浸腐蚀实验分析表层合金化样品的耐腐蚀性能。采用原子力显微镜测试样品的表面电势,分析了Co/Cu表层合金化NdFeB磁体的耐蚀机理。结果表明:Co/Cu合金化层降低了NdFeB磁体表层主相与晶间相之间的电势差,从而有效提升其本征耐腐蚀性能。在800℃扩散15 min的条件下制备的样品的耐腐蚀性能达到最优,自腐蚀电位为-0.846 V,自腐蚀电流密度为3.573×10^(-7)A·cm^(-2),相较于原始NdFeB磁体,自腐蚀电位正移0.223 V,自腐蚀电流密度降低了约3个数量级,在3.5 mass%NaCl溶液中全浸腐蚀实验时间可达到20 h,相较原始NdFeB磁体的1 h,表现出优越的耐腐蚀性能。In response to the problem of poor intrinsic corrosion resistance of NdFeB magnets,a Co/Cu alloying layer was prepared on the surface of NdFeB magnets through magnetron sputtering combined with vacuum diffusion treatment.Phase structure,elemental composition and morphology of surface alloyed magnets were analyzed by X-ray diffractometer and scanning electron microscopy.The corrosion resistance of surface alloyed samples was evaluated using dynamic potential polarization,AC impedance spectroscopy,and static full immersion corrosion experiments.The surface potential of the samples was measured using atomic force microscopy,and the corrosion resistance mechanism of Co/Cu surface alloyed NdFeB magnets was analyzed.The results show that the Co/Cu alloying layer reduces the potential difference between the main phase and intergranular phase on the surface of NdFeB magnets,effectively improving their intrinsic corrosion resistance.The corrosion resistance of the sample prepared under the condition of diffusion at 800℃for 15 min reaches its optimal level,with a self corrosion potential of-0.846 V and a self corrosion current density of 3.573×10^(-7)A·cm^(-2).Compared with the original NdFeB magnet,the self corrosion potential shifts forward by 0.223 V,and the self corrosion current density decreases by about 3 orders of magnitude.The full immersion corrosion test time in 3.5 mass%NaCl solution can reach 20 h,showing superior corrosion resistance compared to the 1 h of the original NdFeB magnet.

关 键 词：NDFEB Co/Cu合金化层 磁控溅射 晶界扩散 耐腐蚀性能 

分 类 号：TG174.44[金属学及工艺—金属表面处理]