Effect of porosity sealing treatments on the corrosion resistance of high-velocity oxy-fuel (HVOF)-sprayed Fe-based amorphous metallic coatings
Effect of porosity sealing treatments on the corrosion resistance of high-velocity oxy-fuel (HVOF)-sprayed Fe-based amorphous metallic coatings
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DOI：
10.1016/j.surfcoat.2011.08.045
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发表时间：
2011-12
影响因子：
5.4
通讯作者：
Yongguang Wang;Shuai Jiang;Y. Zheng;W. Ke;W. Sun;Jinxiu Wang
中科院分区：
文献类型：
--
作者：
Yongguang Wang;Shuai Jiang;Y. Zheng;W. Ke;W. Sun;Jinxiu Wang
采用正硅酸钠（Na 3SiO 4）、磷酸铝（AlPO 4）和铈盐密封剂对高速氧燃料喷涂FeCrMoMnWBCSi非晶态金属涂层进行密封。密封涂层的微观结构，其特征在于通过扫描电子显微镜，能谱仪，和X射线衍射。采用动电位极化、循环极化、电化学阻抗谱和Mott-Schottky试验等电化学方法研究了腐蚀行为。结果表明，经封孔处理后，三种封孔涂层的耐均匀腐蚀性能均得到了显著提高，钝化电流密度降低了一个数量级。AlPO 4密封剂可渗透涂层不小于50μm，提高涂层硬度，使涂层耐腐蚀性更均匀，耐点蚀性能较好，可在长期腐蚀和/或磨损环境中使用。铈盐封孔涂层具有较好的耐点蚀性能，但在微裂纹局部区域的耐腐蚀性能较差，实际上可用于临时防腐蚀。Na 3SiO 4封孔涂层具有较好的耐均匀腐蚀性能和较差的耐点蚀性能，可用于短期腐蚀环境。钝化膜的稳定性影响封孔涂层的腐蚀行为。在长期浸泡试验中，AlPO 4密封涂层作为保护性钝化膜表现更好，缺陷浓度更低，保护性钝化膜更强。
High-velocity oxy-fuel-sprayed FeCrMoMnWBCSi amorphous metallic coatings were sealed with sodium orthosilicate (Na3SiO4), aluminium phosphate (AlPO4), and cerium salt sealants. The microstructure of the sealed coatings was characterised by scanning electron microscopy, energy dispersive spectrometer, and X-ray diffraction. Corrosion behaviour was examined using electrochemical methods of potentiodynamic polarisation, cyclic polarisation, electrochemical impedance spectroscopy, and Mott–Schottky tests. The results indicated that the uniform corrosion resistance of the three sealed coatings was enhanced greatly, and the passive current densities were decreased by one order of magnitude after the sealing treatments. The AlPO4sealant can penetrate the coatings by no less than 50μm and enhance their hardness, which exhibited a more uniform corrosion resistance, fairly good pitting corrosion resistance, and can be applied in long-term corrosive and/or abrasive environments. The cerium salt-sealed coating showed better pitting corrosion resistance but inferior corrosion resistance in the local regions of micro-cracks, which was practically used for temporary corrosion protection. The Na3SiO4-sealed coating showed better uniform corrosion resistance and inferior pitting corrosion resistance, which can be applied in short-term corrosion environments. The stability of the passive film affected the corrosion behaviour of the sealed coatings. The AlPO4-sealed coating performed better as a protective passive film during the long-term immersion test for a lower defect concentration and a more protective passive film.