Pretreatment of carbon steel with silane film modified with a mixture of garlic and cocoa

In the recent years, many studies have been conducted to improve the properties of hybrid silane films, obtained by the sol-gel route, modified with corrosion inhibitors to improve the anti-corrosion properties. The inhibitors obtained from nature (green inhibitors) replace synthetic inhibitors and even rare earth elements (harmful to the environment). Within this approach, this work aims to evaluate the corrosion resistance of the modified TEOS/GPTMS (Tetraethyl orthosilicate/3-Glycidoxypropyltrimethoxysilane) hybrid film with the mixture of the garlic peel and cocoa shell powders as a pre-treatment of SAE (Society of Automotive Engineers) 1008 carbon steel, in which were added different proportions (1:1, 1:2, 2:1) of these mixtures powders, the best mixture ratio was Garlic 1:2 Cocoa. Corrosion resistance was evaluated using electrochemical techniques such as open circuit potential, electrochemical impedance spectroscopy, linear polarization resistance and Tafel polarization curves, in 0.1 mol L⁻¹ NaCl solution. In addition to the scanning vibrating electrode technique, in 0.01 mol L⁻¹ NaCl solution. Film morphology and elements analyses were evaluated by scanning electron microscopy with energy-dispersive spectroscopy. The chemical characterization of the film was obtained by Fourier transform infrared spectroscopy. Physical properties were analyzed by the techniques of contact angle, roughness profile and dry layer thickness. The results of the different techniques indicate that the film modified with the mixture of natural inhibitors has improved anti-corrosive properties compared to the film without natural green inhibitors.