Evaluation of steel/primer based on chestnut tannin/paint film systems by EIS

Abstract

The influence ofa tannin pretreatment applied to slightly rusted steel panels on the anticorrosive performance ofalkyd paint systems has been investigated using electrochemical impedance spectroscopy (EIS) and open circuit potential measurements. From EIS and corrosión potential data analysis it was found that (1) there is not a significant influence of the tannin pretreatment on the anticorrosive protection level, ivhich depends particularly on the barrier effect afforded by the applied paint system (however, as the corrosión process starts, tannins may cause the repassivation of steel); (2) the enhancement ofthe protection level afforded by the tannin primer was restricted to short immersion periods and corrosive media that were not very aggressive; and (3) water uptake was not significantly affected by the presence of the tannin primer