Electrochemical investigation of graphene on the corrosion of scratched polyurea based organic coating

It is still a contentious issue whether graphene is added as filler to the organic coating is a metal corrosion inhibitor or a promoter. To address this issue, this study provides a deep understanding of the effects of highly conductive graphene on corrosion promotion of polyurea-based organic coating via scanning vibrating electrode technique (SVET) and electrochemical impedance spectroscopy (EIS) investigations. The investigation shows that, with the enhancement of graphene loading (0.05 wt% similar to 1 wt%), corrosive promotion effects near the scratch position for different samples are evidently observed and quantitatively detected, specifically, the total anodic currents increased from 0.83 to 19.75 mu A. And the final results have revealed that a small proportion of graphene (similar to 1.05 x 10(-10) S m(-1)) are likely to induce accelerated local galvanic corrosion in the local area of damaged coating. This study undoubted helps to develop polyurea based hybrid coatings efficiently for anticorrosive applications, and call for attention to the damage to the protected metal caused by the high conductivity of the coating matrix.