Elaboration of γ-glycidoxypropyltrimethoxysilane coating on AA2024-T3 aluminum alloy: Influence of synthesis route on physicochemical and anticorrosion properties

Abstract

The deposition of γ-glycidoxypropyltrimethoxysilane (γ-GPTMS) film onto AA2024-T3 aluminum alloy surface was performed via two techniques: dip-coating and electrodeposition. The electrodeposited coatings were performed under potentiostatic control at different cathodic potentials (namely −0.80, −1.30 and −1.70 V vs.SCE).γ-GPTMS films were characterized by physical, microscopic and spectroscopic techniques: Pull-off test, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Fourier Transform Infrared Attenuated Total Reflectance (FTIR-ATR) and X-Ray Photoelectron Spectroscopy (XPS). The electrochemical behaviors of coatings were assessed in chloride solution by means of Electrochemical Impedance Spectroscopy (EIS).The synthesis conditions have shown a key role in the morphology and the anticorrosion performance of γ-GPTMS coating.Results revealed the uneven nature of the dip-coated film that resulted in a non-satisfactory anticorrosion performance. For the electrodeposited coatings, the protectiveness was dictated by the imposed potential value. The film electrogenerated at −0.80 V vs.SCE possessed the best protective performance. Moreover, it was found to be uniform, compact and proved superior adhesion strength when compared to the dip-coated film.