Synergistic effects of fluid flow and sand particles on erosion–corrosion of aluminum in ethylene glycol–water solutions

The synergistic effects of fluid flow and sand particles on erosion–corrosion of 3003 aluminum (Al) alloy in ethylene glycol–water solution that simulates the automotive engine coolant were studied through a rotating disk electrode by electrochemical measurements. It was found that, in the absence of sand particles, the anodic current density of Al electrode decreases with the increase in electrode rotating speed, which is attributed to the enhanced electrode oxidation accompanying with accelerated oxygen diffusion and reduction. Mass-transport plays an important role in electrode process, as indicated by the presence of diffusive impedance. With the addition of sand particles, the de-stabilization of electrode is predominant and the anodic current density increases with the electrode rotation speed, which is attributed to the enhanced impact damage to electrode by sand particles. The electrode roughening effect due to sand impact is indicated by the presence of inductive loop in impedance plots. The variation of sand particle size does not have apparent effect on polarization behaviour of Al electrode, while an elevated temperature increases significantly the anodic current density of the electrode. There exists a synergism of fluid flow and sand impact on electrochemical corrosion behaviour of Al electrode.