XPES of 1,2,3-benzotriazole nanolayers formed on iron surface

The effect of 1,2,3-benzotriazole (BTA) on the electrochemical behavior of St3 steel in different environments, as well as the adsorption of BTA on the steel surface, is studied using the XPES technique. Based on the XPES data using the MultiQuant program, the thickness of the layers formed on the St3 steel surface are calculated. In neutral borate solutions, a thin protective layer of iron-BTA complex with a thickness of 0.7-1.5 nm, which completely suppresses the anodic process, but does not prevent the local depassivation in the presence of chlorides, is found to form on the surface of St3 steel. In alkaline solutions, BTA hardly chemisorbs at all, though adding BTA to the solutions and increasing its concentration results in the increase in the pit-formation potential. In sulfuric-acid solutions, a monomolecular layer is formed on the steel surface. Independently of the pH value, the interaction between BTA and iron cations is shown to result in the proton detachment from BTA molecules.