在LY12铝合金表面制备了防护性溶胶凝胶膜层,并研究了乙酸钴的掺杂对膜层耐蚀性能的影响。采用扫描电子显微镜(SEM)和电子能谱(EDS)分别观测溶胶凝胶膜层的微观结构和成分。采用电化学方法研究了乙酸钴浓度对溶胶膜层在浸泡实验中耐蚀性的影响;通过观察人为缺陷处在0.05 mol/L NaCl腐蚀溶液中形貌、成分的变化,对乙酸钴的缓蚀机理进行了探讨。研究表明,掺杂适量的乙酸钴不仅可以提高溶胶凝胶膜层的耐蚀性能,而且可以为受到破坏的溶胶凝胶膜提供缓蚀性能。然而相对高浓度的掺杂量则会降低膜层的稳定性,破坏溶胶凝胶膜层的腐蚀防护性能。
The aim of this study is to investigate the effect of cobaltous acetate doping on the corrosion resistance of sol-gel coatings on aluminium alloy LY12. The morphology and chemical composition of the coatings are investigated respectively by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) are used to study the corrosion resistance mechanism of the coatings immersed in 0.05 mol/L NaCl solution. The results demonstrate that the doping of cobaltous acetate represented a remarkable improvement for the corrosion resistance of the coatings. In addition, the immersion test reveales that cobaltous acetate doping provided corrosion inhibition effect to the coatings. However, cobaltous acetate of relatively high concentration in sol-gel coatings might undermine both the stability and the corrosion resistance performance of the coatings after immersion.
[1] Poznyak S K, Zheludkevich M L, Raps D, et al. Preparation and corrosion protective properties of nanostructured titania-containing hybrid sol-gel coatings on AA2024[J]. Progress in Organic Coatings, 2008, 62(2): 226-235.
[2] Lanaka S V, Zheludkevich M L, Yasakau K A, et al. Nanoporous titania interlayer as reservoir of corrosion inhibitors for coatings with self-healing ability[J]. Progress in Organic Coatings, 2007, 58(2-3): 127-135.
[3] Wang D H, Bierwagen G P. Sol-gel coatings on metals for corrosion protection[J]. Progress in Organic Coatings, 2009, 64(4): 327-338.
[4] Zand B N, Mahdavian M. Corrosion and adhesion study of polyurethane coating on silane pretreated aluminum[J]. Surface & Coatings Technology, 2009, 203(12): 1677-1681.
[5] Feng Z, Liu Y, Thompson G E, et al. Sol-gel coatings for corrosion protection of 1050 aluminium alloy[J]. Electrochimica Acta, 2010, 55(10): 3518-3527.
[6] Vermaa A, Bakhshib A K, Agnihotrya S A. Effect of citric acid on properties of CeO2 films for electrochromic windows[J]. Solar Energy Materials & Solar Cells, 2006, 90(11): 1640-1655.
[7] Xu Y, Zeng Z. The preparation, characterization, and photocatalytic activities of Ce-TiO2/SiO2[J]. Journal of Molecular Catalysis A: Chemical, 2008, 279(1): 77-81.
[8] He X D, Shi X M. Self-repairing coating for corrosion protection of aluminum alloys: a proof-of-concept using cagelike smart particles//Transportation Research Board 87th Annual Meeting. 2008.
[9] Moutarlier V, Neveu B, Gigandet M P. Evolution of corrosion protection for sol-gel coatings doped with inorganic inhibitors[J]. Surface & Coatings Technology, 2008, 202(10): 2052-2058.
[10] 杨志成,田志强,孔小东. 阳极极化法分析缓蚀剂对Al-Mn-Mg合金的缓蚀作用[J]. 清洗世界, 2007, 23(9): 5-10. Yang Zhicheng, Tian Zhiqiang, Kong Xiaodong. Effects of inhibitors on corrosion resistance of Al-Mn-Mg alloy researched by polarization technique[J]. Cleaning World, 2007, 23(9): 5-10. (in Chinese)
[11] 曹楚南,张鉴清. 电化学阻抗谱导论[M]. 北京:科学出版社,2002. Cao Chunan, Zhang Jianqing. Introduction of electrochemical impedance spectroscopy[M]. Beijing: Science Press, 2002. (in Chinese)
[12] Zhang S Y, Li Q, Chen B, et al. Preparation and corrosion resistance studies of nanometric sol-gel-based CeO2 film with a chromium-free pretreatment on AZ91D magnesium alloy[J]. Electrochimica Acta, 2010, 55(3): 870-877.
[13] Hosseini S M A, Jafari A H, Jamalizadeh E. Self-healing corrosion protection by nanostructure sol-gel impregnated with propargyl alcohol[J]. Electrochimica Acta, 2009, 54(28): 7207-7213.
CJA