Influence of silane coupling agent on the conversion film forming of galvanized steel treated with cerium salt

Abstract

The influence of silane coupling agent on the film forming of galvanized steel treated with cerium salt was studied by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), and the corrosion resistance of conversion films was analyzed by electro interstitial scanning (EIS). The results show that silane coupling agent KH-570 has significant influence on the compactness and homogeneity of cerium conversion films, and the process of film forming is promoted by increasing the content of tervalent and tetravalent cerium oxide. The impedance value of the cerium conversion film, especially modified with KH-570, is greater than that of the base metal, which reveals that it is necessary to add silane coupling agent to the film-forming solution in order to improve the corrosion resistance of the conversion film.

Keywords

galvanized metal / cerium compounds / thin films / silanes coupling agents

References

[1] Hinton B.R.W., Wilson L. The corrosion inhibition of zinc with cerous chloride. Corros. Sci., 1989, 29(9): 967

[2] Hinton B.R.W. Corrosion inhibition with rare earth metal salts. J. Alloys Compd., 1992, 180(1–2): 15

[3] Montemor M.F., Simões A.M., Ferreira M.G.S. Composition and behaviour of cerium films on galvanised sition and behaviour of cerium films on galvanised steel. Prog. Org. Coat., 2001, 43, 274

[4] Montemor M.F., Simões A.M., Ferreira M.G.S. Composition and corrosion behaviour of galvanised steel treated with rare-earth salts: the effect of the cation. Prog. Org. Coat., 2002, 44, 111

[5] Sánchez M., Alonso M.C., Cecílio P., Montemor M.F., Andrade C. Electrochemical and analytical assessment of galvanized steel reinforcement pre-treated with Ce and La salts under alkaline media. Cem. Concr. Compos., 2006, 28, 256

[6] Lu J.T., Wu H.J., Kong G., Che C.S., Xu Q.Y. Growth and corrosion behavior of rare earth film on hot-dip galvanized steel. Trans. Nonferrous Met. Soc. China, 2006, 16, 1397

[7] Peng T.L., Man R.L. Study on passivation effect of lanthanum and cerium on galvanized steel. J. Chin. Rare Earth Soc., 2008, 26(5): 598.

[8] Yang L., Liu G.M., Qian Y.H., Du N. Electrochemical behavior of the cerium passivating film on galvanized steel. Surf. Technol., 2006, 35(6): 11.

[9] Palomino L.M., Suegama P.H., Aoki I.V., Montemor M.F., De Melo H.G. Electrochemical study of modified non-functional bis-silane layers on Al alloy 2024-T3. Corros. Sci., 2008, 50, 1258

[10] Chico B., Galván J.C., de la Fuente D., Morcillo M. Electrochemical impedance spectroscopy study of the effect of curing time on the early barrier properties of silane systems applied on steel substrates. Prog. Org. Coat., 2007, 60, 45

[11] Peng T.L., Man R.L., Xu B., Qiao L.J. Influence of silane Γ-APS pre-film on passivation of galvanized steel by rare earth lanthanum. Corros. Sci. Prot. Technol., 2008, 20(5): 350.

[12] Xu B., Man R.L., Ni W.D., Hu Y., Gao X.Y., Yan S., Shi Y. Preparation of compound film of silane and cerium salt on galvanized steel and its corrosion resistant property. Paint Coat Ind., 2007, 37(12): 46.

[13] Mei Y., Yan J.P., Nie Z.R. XPS study on the influence of calcination conditions to cerium ion valence. Spectrosc. Spect. Anal., 2010, 30(1): 270.

[14] Song Y.K., Mansfeld F. Evaluation of the corrosion resistance of different galvanized steels treated in a cerium salt solution. Mater. Corros., 2005, 56(4): 229

[15] Lü X.H., Xu W.Y. CO₂ corrosion behavior of P110 steel at the simulated environments of oil field. Mater. Sci. Eng., 2008, 26(4): 535.

[16] Cao C.N. The Principle of Corrosion Electrochemistry, 2004, Beijing, Chemical Industry Press, 48.

[17] Wang X.M., Li A.J., Li G.L., Guan C.S. Studies on the application for SCA in the metal pretreatment of anti-corrosion coatings. J. Inorg. Mater., 2005, 23(1): 146.

[18] Liu J., Hu J.M., Zhang J.Q., Cao C.N. Progress in anti-corrosive treatment of metals by silanization. J. Chin. Soc. Corros. Prot., 2006, 26(1): 59.