The protective power of organic coatings strongly depends on substrate surface pre-treatments. They are supposed to improve system corrosion resistance as well as the adhesion of any polymeric layers applied.Chromatation has been used because of its inhibition power against general and localized corrosion (1-5). This process is increasingly restricted owing to its high chemical risk. The use of chromates is indeed hazardous for professionally exposed operators as well as for the environment. In order to use these substances, a careful control of all process parameters is required of the work environment and related wastes.These operating conditions, involving high costs and risks, have spurred the recent trend to replacing this process with one involving lower risks. Investigations carried out in this direction have shown that surface pre-treatment with fluotitanation in general offers a good inhibition power against general corrosion together with low environmental impact. It could thus be considered as an alternative method to conventional ones (6, 7). Previous studies carried out at I.C.M.M., using aqueous 3.5 percent NaCl solutions have shown that fluotitanates have a significant inhibiting action, although not as good as chromates (8).The aim of this work was to study the passive film formed by a surface fluotitanation treatment on aluminum substrate, in order to understand the protective mechanism against corrosive attack.
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