Phosphating passivation of vacuum evaporated Al/NdFeB magnets boosting high anti-corrosion performances
Phosphating passivation of vacuum evaporated Al/NdFeB magnets boosting high anti-corrosion performances
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DOI：
10.1016/j.surfcoat.2020.126115
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发表时间：
2020-10
影响因子：
5.4
通讯作者：
Jing Chen-;Hongyi Yang;Guangqing Xu;Pengjie Zhang;Jun Lv;Wei‐Che Sun;Bingshan Li;Jun Huang;
中科院分区：
文献类型：
--
作者：
Jing Chen-;Hongyi Yang;Guangqing Xu;Pengjie Zhang;Jun Lv;Wei‐Che Sun;Bingshan Li;Jun Huang;
采用气相法对铝包覆钕铁硼磁体表面进行磷化钝化。利用X射线衍射、扫描电子显微镜和X射线光电子能谱对样品的表面形貌、结构和元素组成进行了表征。通过中性盐雾试验、动电位极化曲线和电化学阻抗谱测试，分析了磷化钝化处理后的Al/NdFeB磁体的耐蚀性能。通过分析涂层在3.5mass%NaCl溶液中浸泡不同时间的腐蚀形貌、动电位极化曲线和表面元素组成，研究了涂层的腐蚀过程和腐蚀机理。采用气体磷化技术可以实现铝包覆钕铁硼磁体的表面钝化，有效提高铝涂层的耐蚀性。优化后的磷化温度为300 °C时，NSS时间由96 h提高到288 h。气相磷化能有效封闭真空蒸镀铝涂层中的孔隙，并在涂层表面形成磷化钝化膜，有助于提高铝涂层NdFeB磁体的耐蚀性能。
A phosphating passivation is conducted on the surface of Al coated NdFeB magnets by a gaseous process. The surface morphology, structure and elemental compositions of the samples are characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy, respectively. The anti-corrosion performances of the phosphating passivated Al/NdFeB magnets are analyzed by neutral salt spray test, potentiodynamic polarization curve and electrochemical impedance spectroscopy measurements. The corrosion process and corrosion mechanism of the samples are studied by analyzing the coating morphologies, potentiodynamic polarization curves and surface elemental compositions during the immersion test in 3.5 mass% NaCl solution for different time. The surface passivation of Al coated NdFeB magnets can be realized by gaseous phosphating technology, which can effectively improve the corrosion resistance of Al coating. The optimized sample obtained with phosphating temperature at 300 °C achieves the improvement of NSS time from 96 h to 288 h. Gaseous phosphating can effectively seal the pores in vacuum evaporated Al coatings, and form a phosphating passivation film on the coating surface, which contribute to the enhancement of anti-corrosion performances of Al coated NdFeB magnets.