Sol-gel based hybrid silane coatings for enhanced corrosion protection of copper in aqueous sodium chloride

Abstract

In this study, various concentrations of p-aminothiophenol doped 3-glycidoxypropyltrimethoxysilane based sol-gel matrices (PATP-GPTMS) are prepared through hydrolysis and condensation reactions. The prepared PATP-GPTMS sol-gel is applied on the polished copper (Cu) surface (PATP-GPTMS/Cu) by self-assembly technique. The surface profile of resultant coatings are characterized by important analytical tools such as Fourier transform infra-red (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and stylus profilometer. The surface morphologies of coatings are acquired by scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM) techniques. The FT-IR and XPS results revealed the linking of PATP and thiol monolayer on Cu surface in 0.1 M PATP-GPTMS/Cu coating. Further, the corrosion protection ability of PATP-GPTMS/Cu coatings in 3.5% sodium chloride (NaCl) medium are studied by common electrochemical tools. The electrochemical impedance spectroscopy (EIS) results showed that PATP-GPTMS/Cu coating exhibit improved corrosion resistance than the undoped GPTMS/Cu coating. The maximum corrosion inhibition efficiency of 96.39% is achieved on 12 h self-assembly technique based sol-gel coating of 0.1 M PATP-GPTMS/Cu by polarization method. All the results exposed that, the PATP-GPTMS/Cu coating enhanced the corrosion protection of Cu in aqueous 3.5% NaCl medium.