Cavitation Corrosion Behavior of Anodized Aluminum Alloy

Abstract

Abstract The cavitation corrosion behavior and surface morphology of anodized aluminum alloy in 3.5% sodium chloride (NaCl) solution were investigated using weight loss and scanning electron microscopy. The electrochemical corrosion mechanism during cavitation corrosion was studied using electrochemical polarization and electrochemical impedance spectroscopy (EIS). The cavitation corrosion process could be divided into three stages: quick removal of the porous outer layer, slowly fragmenting and removing of the dense inner layer, and fast erosion of the aluminum alloy. Increasing the thickness of the anodized layer improved the cavitation corrosion resistance of the anodized aluminum alloy. Electrochemical corrosion processes under cavitation conditions were controlled by mixed cathodic and anodic processes. EIS spectra of anodized aluminum alloy under cavitation conditions resembled those from porous electrodes. Cavitation accelerated the electrochemical corrosion. Cavitation corrosion of anodized aluminum alloy showed strong synergism between mechanical and electrochemical corrosion factors.