It was observed experimentally that a chemical reaction limiting current can be affected by flow. In the present study a new more general expression than the one found in literature was derived for the superposition of the diffusion and chemical reaction controlled limiting currents . It was found that their interaction in the case of CO 2 corrosion is significant at temperatures lower than 40°C and velocities higher than 1 m/s when the mass transfer layer is of the similar thickness as the reaction layer.