Comprehensive Analysis of Silane Coatings on Carbon Steel: From Microscopy to Quantum Chemistry

In the realm of eco-friendly metal pretreatment methods as a substitute for chromates, silanes have emerged as a prominent option for augmenting the adhesion of polymer coatings onto the surfaces of carbon steel. However, there exists a notable dearth of research at the nanoscale, delving into the interaction between silanes and carbon steel surfaces. To address this gap, silane coatings were applied on the carbon steel surface via an electrodeposition process. A comprehensive investigation was conducted to elucidate the interfacial bonding characteristics and corrosion inhibition mechanism between silanes and hydroxylated carbon steel surfaces using an array of analytical techniques, including scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, molecular dynamics (MD) simulations, and density functional theory (DFT) calculations. The results revealed that the silane layer achieved stable adsorption, with a contact angle of 91.29°, forming a robust interface with the passivation layer on the carbon steel surface. The hydrogen bonding interactions between the silanol groups in the silane molecules and the hydroxyl groups within the passivation film on the carbon steel surface were identified as the primary mechanism responsible for this adsorption. This integrated approach combining experimental and computational methods provides new insights into the interfacial bonding and corrosion inhibition behavior of silane coatings, thereby offering a scientific foundation for their practical application in metal protection systems.