Comparison of protective coatings prepared from various trialkoxysilanes and possibilities of spectroelectrochemical approaches for their investigation

Abstract

Abstract Herein protective coatings against corrosion are compared with regard to their protective efficiency. The coatings had been prepared over the course of time from differently trialkoxysilyl-functionalized commercial or synthesized precursors but were tested using the same techniques and in similar conditions. The coatings are compared according to the existing data on contact angles for water, free surface energy, thickness and protective efficiency, expressed in term of corrosion current density. Moreover, the influence of differently functionalized trialkoxysilyl precursors on the crosslinking of coatings is regarded. It was also noted that too hydrophobic additives can introduce certain defects which can detrimentally influence the protective efficiency. Spectroelectrochemical approach can give important insights into the degradation of protective coatings under electrochemically induced loads. Ex situ infrared reflection-absorption (IR RA) spectroelectrochemical approach can identify hydration, breakage of some siloxane bands or changes in the C–H spectral region. Careful examination can confirm the interruption of some bands between alloy and coating that are responsible for its adhesion. Raman imaging is appropriate to follow the formation and growth of pits that form in the coatings.