Protective Effects of 2-Thioquinazolin-4-One Derivatives on Steel 20 in Various Corrosive Media

The dependence of the inhibitive effects of new 2-thioquinazolin-4-one derivatives on the corrosivity and pH of the medium was studied. The test compounds were found to effectively inhibit the acid corrosion of steel 20; when combined with (NH4)2MoO4, 2-thioquinazolin-4-one derivatives inhibit both the cathodic and anodic processes of electrochemical corrosion in neutral (0.3 to 0.6% NaCl) and alkaline media (0.1 M NaOH). In 3% NaCl, the test compounds stimulated corrosion.