What causes corrosion from ethylene glycol?
Q: If a mixture of 50% warm ethylene glycol C2H6O2 and 50% water comes in contact with 6xxx series aluminum, it pits the bare machined surface. What is the reaction product? Will any product of oxidation/reduction get deposited? What is the reaction chain? A: I have limited experience with aluminum alloys so I am not sure of the reaction products or the exact corrosion mechanism in this case. However, most corrosion caused by ethylene glycol is related to its decomposition to organic acids (such as glycolic acid) especially under elevated temperatures. The corrosion of aluminum alloy in the presence of ethylene glycol is most likely a result of acidic attack by these acids. It is known that impurities often found in ethylene glycol/water mixtures, such as ferric, copper, and chloride ions, can accelerate this corrosion. Corrosion problems with ethylene glycol/water mixtures can be minimized or eliminated by using ethylene glycol that contains inhibitors. Most commercial ethylene glycol
