Synergistic corrosion behavior of Cl− and oxalic acid on ADC12 aluminum alloy

Purpose As a commonly engine coolant, ethylene glycol can produce corrosive acid byproducts at high temperatures when the car is running, specifically oxalic acid (OA), which can shorten the service life of engine. At the same time, chloride ions can also be introduced during coolant preparation processes. Therefore, this paper aims to investigate the synergistic corrosion behavior of Cl − and OA on ADC12 aluminum alloy. Design/methodology/approach The electrochemical tests, scanning electron microscopy, energy dispersive spectrometer, X-ray diffraction and X-ray photoelectron spectroscopy) were used. Findings The results showed that the corrosion rate of the aluminum alloy increased with the increase of OA and Cl − concentrations. After adding Cl − , the surface film of the aluminum alloy was further damaged, Cl − has a synergistic effect with OA and their interaction further accelerated the corrosion of the aluminum alloy. Nevertheless, as the immersion time increased, the corrosion rate of the aluminum alloy gradually diminished due to the formation of aluminum oxalate. Originality/value The corrosion of ADC12 aluminum alloy was studied in OA, Cl − and their mixed solutions; the synergistic effect of OA and Cl − on the corrosion of ADC12 aluminum alloy was discussed, and aluminum oxalate formed inhibited its corrosion.