Effect of Inhibitors on the Corrosion of Automotive Aluminum Alloy in Ethylene Glycol-Water Mixture

The effect of some inhibitors consisting of sodium nitrite (NaNO₂), sodium nitrate (NaNO₃), sodium molybdate (Na₂MoO₄), and sodium silicate (Na₂SiO₃) on the corrosion behavior of aluminum alloy 3303 (UNS A93303) in a water and ethylene glycol (C₂H₆O₂) mixture was investigated. In the first part, the tests were established without any galvanic coupling. In the second part, the tests were established with galvanic connections between the aluminum alloy and mild steel, stainless steel, copper, brass, and solder. Results show that the best corrosion inhibitor in both situations is sodium nitrate, according to its abilities to reduce corrosion rate, passivate the aluminum surface, and stop pitting corrosion.