Self-assembling Of Silane On The Surface Of Stainless Steel And Its Corrosion Inhibition Performance

The430stainless steel (430SS) has a great demand in society, but it’s susceptible to corrosion limits the application in high-end commodities, therefore, it is very important to improve the anti-corrosion property of stainless steel. Alkylsilane SAMs, as a simple, environmentally friendly and excellent corrosion resistance technique, are very popular with corrosion resistance treatment on the surface of the metal. The study of alkylsilane SAMs have focused on the surface of aluminium, magnesium and carbon steel, however, studies about silane self-assembled monolayers on the430stainless steel surface were rarely reported.3-glycidoxypropyltrimethoxysilane (GPTMS) is a corrosion inhibitor, the epoxy groups in the end of the GPTMS molecule can react with the hydroxyl groups, and other active groups in the corrosion inhibitor molecules, if GPTMS can be absorbed on the surface of stainless steel perfectly, the self-assembled bilayers or mutilayers can be formed by reaction between epoxy groups and active groups. Due to1H,1H,2H,2H-Perfluorodecyltriethoxysilane (PFDS) has low surface energy and high hydrophobicity, so PFDS could form hydrophobic SAMs. In this paper, we used GPTMS and PFDS molecule to treatment of the surface of stainless steel, the train of thought of GPTMS/PFDS bilayers were proposed according to the structure of two kinds of molecules. The adsorption behavior and the corrosion inhibition performance of both GPTMS, PFDS SAMs and GPTMS/PFDS bilayers were studied by polarization curves, Electrochemical Impedance Spectroscopy (EIS), Attenuated Total Reflection-Fourier Transform Infrared spectroscopy (FTIR-ATR), contact angle measurements, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy(AFM). The main conclusions are as following.1.GPTMS can formed SAMs on the surface of the430stainless steel successfully, and the corrosion resistance performance of GPTMS SAMs is enhanced with the increase of the concentration of GPTMS, the most suitable concentration is5mM; The anti-corrosion properties of GPTMS SAMs is improved with the increase of the self-assembly time, the adsorption of GPTMS reaches balance at the self-assembly time of6h, and the GPTMS SAM prepared at6h is the most densely; There more hydroxyl groups on the surface of the stainless steel treated with sodium metasilicate and acetic acid after the oxidation.2. The PFDS SAMs can prepared by immersion methods. The corrosion resistance performance of PFDS SAMs is enhanced with the increase of the concentration of PFDS, in consideration of the steric hindrance, the optimal concentration is confirmed lOmM; The anti-corrosion properties of GPTMS SAMs is improved with the increase of the self-assembly time, while the self-assembly time reaches2h, the corrosion inhibition properties is almost constant; The temperature of curing is too high or too low, which is go against the formation of the PFDS SAMs, the SAMs prepared at the condition of the curing temperature120℃for1h is more perfect.3. GPTMS/PFDS bilayers could be formed by the reaction of the epoxy groups in the end of GPTMS molecules with the silicon hydroxyl groups in the PFDS molecules; The surface of the GPTMS SAM changes from hydrophilic to hydrophobicity, and the corrosion inhibition performance is improved significantly. The optimal conditions for forming the GPTMS/PFDS bilayers are that the pH and temperature of PFDS solution are4å'Œ25℃, respectively.