Investigation of erosion-corrosion of 3003 aluminum alloy in ethylene glycol-water solution by impingement jet system

Erosion-corrosion (E-C) of 3003 aluminum (AI) alloy in ethylene glycol-water solutions were studied by weight-loss and electrochemical measurements as well as surface characterization through an impingement jet system. All alloy E-C is dominated by erosion components, i.e., pure erosion and corrosion-enhanced erosion, which account for 92-97% of the total E-C rate under the various conditions in this work. Contribution from corrosion components, including pure corrosion and erosion-enhanced corrosion, is slight. With the increase of fluid flow velocity and sand concentration, the total E-C rate increases. Compared with the significant increase of the rates of erosion components, the increase of the rate of corrosion component is negligible. Upon fluid flow, passivity of Al alloy that develops in static solution cannot be maintained, and an activation mechanism dominates the corrosion process of Al alloy. The effect of fluid impact angle on Al alloy E-C depends on the competitive effect of normal stress and shear stress. Under normal impact, the surface film would be broken and damaged, but still remain on the electrode surface to provide somewhat protection. With the decrease of impact angle, shear stress becomes dominant, and it would thinner and even completely remove the film. The enhanced surface irregularity of electrode under fluid impact is indicated by the presence of inductive loop in EIS plots. The effects of impact angle on electrode surface status and E-C rate are confirmed by surface morphology observation. (C) 2008 Elsevier Ltd. All rights reserved.