Influence of Some Azo—Azomethine Compounds and Their Complexes on the Corrosion Inhibition of Copper in Chloride Media

Abstract

The inhibiting effects of azo—azomethine compounds and their copper complexes were investigated to evaluate their efficiency as corrosion inhibitors for copper in 1.0 M chloride solutions (NaCl) under various conditions using weight loss, electrochemical measurements and solution analyses. The results obtained indicated a remarkable decrease in the corrosion rate in the presence of 20 mmol/l azo I—azomethine I at room temperature. To study the nature of the solid products formed under free corrosion conditions or with the additive, the surface morphology at the end of the immersion tests was examined using infrared spectroscopy (IR). The surface film was identified as a Cu(II) complex totally covering the surface of the metal, exhibiting strong corrosion inhibition. The formation of the Cu(II) complex was accomplished by the adsorption of the azo—azomethine onto the copper surface.