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The corrosion protection property and morphology of colloidal silica conversion films as an alternative to chemical conversion coating(CCC) films were examined. The corrosion behavior was investigated in 3% NaCl solution using electrochemical techniques. Corrosion was implied by the appearance of red rust on the specimen surface. The results show that in 3% NaCl solution, red rust appears at 15-20, 55-70, and 75-85 d on Zn-electroplated steel, colloidal silica conversion-coated specimens, and chemical conversion-coated, specimens, respectively. In the salt spray test, the colloidal silica film provides better corrosion protection than CCC film, i.e., red rust appears at 96 h on the Zn-electroplated steel sheet, at 432 h on the CCC films, and at 888 h on silica conversion coating.
The corrosion protection property and morphology of colloidal silica conversion films as an alternative to chemical conversion coating (CCC) films were examined. The corrosion behavior was investigated in 3% NaCl solution using electrochemical techniques. Corrosion was implied by the appearance of red rust on the The results show that in 3% NaCl solution, red rust appears at 15-20, 55-70, and 75-85 d on Zn-electroplated steel, colloidal silica conversion-coated specimens, and chemical conversion-coated, specimens , respectively. In the salt spray test, the colloidal silica film provides better corrosion protection than CCC film, ie, red rust appears at 96 h on the Zn-electroplated steel sheet, at 432 h on the CCC films, and at 888 h on silica conversion coating.