Adsorption of 1,2,3-benzotriazole on zinc surface from phosphate solution

The electrochemical behavior of zinc in phosphate solutions (pH 8.9) containing benzotriazole (BTA) and NaCl is studied. Introduction of up to 15 mmol/L BTA into phosphate solution is found to nearly completely suppress the anodic current and increase the pitting potential. In accordance with XPS data, an oxide-hydroxide layer covered with (ZnBTA2) n protective complex is formed on zinc, phosphate being completely displaced from the surface layer by BTA.