Triazole and thiazole derivatives as corrosion inhibitors for AA2024 aluminium alloy

The 1,2,4-triazole, 3-amino-1,2,4-triazole, benzotriazole and 2-mercaptobenzothiazole were evaluated in the present work as corrosion inhibitors for protection of the 2024 aluminium alloy in neutral chloride solutions. The corrosion protection performance was investigated by means of DC polarization and electrochemical impedance spectroscopy (EIS). Scanning Kelvin probe force microscopy (SKPFM) and atomic force microscopy (AFM) were used to study the evolution of the Volta potential distribution and the surface topography during corrosion tests. The results show that all inhibitors under study confer corrosion protection to the AA2024 alloy forming a thin organic layer on the substrate surface. Benzotriazole and 2-mercaptobenzothiazole offer better corrosion protection in comparison with the other two. The inhibitors studied act decreasing the rate of both the anodic and cathodic processes. In the latter case the dealloying of the copper-reach particles is hindered, slowing down the oxygen reduction. (c) 2005 Elsevier Ltd. All rights reserved.