Corrosion-Electrochemical Behavior of M1 Copper in Aqueous Ethylene-Glycol Media

In aqueous ethylene-glycol media, M1 copper oxidizes to Cu+ ions. In the course of corrosion, dissolved oxygen oxidizes ethylene glycol and Cu+ ions to Cu2 + ions, which, together with ethylene glycol and the products of its oxidation, form complex compounds. In the case of deep ion-exchange purification of a water-ethylene-glycol heat carrier (ρ = 100 kΩ · m), the maximum value of the coefficient of protective action is 70%. With decrease in the concentration of dissolved oxygen to 1 g/m3, under conditions of minimum purification ρ = 5 kΩ · m), this parameter constitutes 77% and grows to 97% for a specific electric resistance of the heat carrier of 50 kΩ · m. Combining both methods of the removal of corrosion-active admixtures (dissolved oxygen and the products of copper and ethylene glycol oxidation), one can enhance substantially the corrosion resistance of copper in water-ethylene-glycol heat carriers.