Aqueous ethylene glycol solutions are widely used as antifreeze in cooling systems. The construction materials of such systems (copper, carbon and stainless steels) may undergo corrosion. In this work, tube samples of St3 steel and M-3 copper were studied. Results on the interaction of Na//2HPO//4 and BTA show that upon introduction of a small amount of BTA into an aqueous solution of ethylene glycol containing Na//2HPO//4 the corrosion rate of steel and copper decreases.