Abstract: The film formation process of corrosion inhibitors on copper in neutral solutionswas studied by combination of photoelectrochemical technique with electrochemical quartzcrystal microbalance(PECQCM).It is found that the film growth on the copper in Na₂SO₄solution with oxidizing inhibitor Na₂CrO₄ follows the parabola type line, while in NaCl solution it appears to be a broken line.The precipitation type inhibitor Na₂SiO₃ will form film onthe copper electrode in NaCl solution, but not in Na₂SO₄ solution.

Key words: corrosion inhibitor, film formation process, copper electrode, photoelectrochemical technique, electrochemical quartz crystal microbalance