This article reports on a comparative study on the corrosion resistance of low-carbon steel substrates pretreated with different silane solutions and painted. The pure silanes used to pretreat the steel panels were 3-aminopropyltriethoxysilane (c-APS), 3-glycidoxypropyltrimethoxysilane (c-GPS), and bis(3-triethoxysilylpropyl)amine. The study also considered other silane solutions with ureido, amino, and epoxy organofunctional groups, and two bis-functional silanes: bis(c-trimethoxysilylpropyl)amine (BAS) and 1,2-bis(triethoxysilyl)ethane (BTSE). A conventional phosphate-type pretreatment was also applied for reference purposes. The pretreated panels were then finished with an alkyd/polyester aminoplast base paint. As a branch test, an acrylic/urethane paint was also applied. Different tests were conducted to evaluate the anticorrosive ability of the different silane/paint systems: outdoor exposure in an atmosphere of moderate aggressivity; accelerated corrosion test (salt fog test); and electrochemical impedance spectroscopy (EIS). The results show that the steel pretreated with certain silanes, especially c-APS, yields similar results to steel subjected to conventional phosphate pretreatment.

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