Electrochemical characterization of metastable pitting of 3003 aluminum alloy in ethylene glycol–water solution

The corrosion and electrochemical behavior of 3003 aluminum alloy in ethylene glycol–water solution were investigated by electrochemical techniques. It is found that the oxide film formed on aluminum depends on the dissolved oxygen in the solution. In the presence of oxygen, a layer of aluminum oxide film forms on the aluminum surface to protect the substrate from corrosion. In the absence of oxygen, the film formed is mainly aluminum-alcohol film that is less compact and less resistant to corrosion. The aluminum oxide film and aluminum-alcohol film have the different susceptibilities to chloride ion attack for pit initiation. There is a higher pitting susceptibility for aluminum oxide-covered electrode. The increase in temperature decreases the resistance of aluminum electrode to corrosion reaction. However, the resistance to pitting corrosion increases.