Expert ForumsCorrosion

Topic: What causes corrosion from ethylene glycol?

anonymous
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?
  • Avatar Brian Dalder Forum Moderator 177 Posts

    Re: What causes corrosion from ethylene glycol?

    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 glycols sold contain these corrosion inhibitors. It is not generally recommended to use uninhibited ethylene glycols for heat transfer applications. If uninhibited ethylene glycol is used, it must be used with caution and carefully monitored.

     

  • Avatar Steven Siepser Community Member 1 Post

    Re: What causes corrosion from ethylene glycol?

    Dear Colleagues, Ehtylene Glycol is the major component of the TKS solution used in-flight for de-icing airplanes in a continuous process of weeping out of the porous front surface of the airfoil. I also have noted that it is often in windshield de-icing solutions. What are the expert's comments on the corrosion effect of these solutions on plexiglass, painted and coated aluminum and metal components of aircraft?
  • Avatar Brian Dalder Forum Moderator 177 Posts

    Re: What causes corrosion from ethylene glycol?

    I am not familiar with the technologies and fluids used for aircraft de-icing. However, if ethylene glycol is involved, I suspect it does not harm the aircraft components because of a combination of one or more of the following:

    1) the temperature is not elevated (elevated temperatures can cause decomposition and acid formation in uninhibited ethylene glycol solutions)

    2) the de-icing fluids contain corrosion inhibitors

    3) the concentration of the de-icing agents is low and therefore does not induce corrosion

    4) the de-icing solutions are already compatible at the concentrations and temperatures of interest


    Regarding auto windshield wiper fluids, in addition to the above, most windshield wiper fluids are mixtures of water and methanol (and not ethylene glycol and water).