An electrochemical investigation into the galvanic corrosion of carbon steel coupled to carbon fibres

The problem of galvanic coupling of mild steel to carbon fibres in aqueous solutions relevant to environmental exposure cases is attacked in this research. Acid sulphate and near neutral chloride and bicarbonate solutions are considered. The application background of this investigation is the mechanical joining of carbon‐fibre reinforced polymer‐matrix composites. This research is based on the following electrochemical measurements: galvanic current, corrosion potential, linear‐sweep voltammetry, electrochemical impedance spectroscopy and time‐dependent impedance. The combination of electrochemical measurements performed directly on the galvanically coupled system and on the single materials exposed to the environments of interest, gives insight into the kinetic and mechanistic factors leading to a given, time dependent behaviour of the galvanic couple. Time drifts of the corrosion performance of the couple were assessed and passivation or localised corrosion phenomena highlighted.