Study on anticorrosion properties of the composite coating based on epoxy/phenolic hybrid containing modified nanosilica by 3-ethoxy vinyl silane on ST12 steel substrate

摘要

: The aim of this study is to investigate the corrosion prevention of the epoxy/phenolic hybrid coating (100:1) and the effect of the silane modified nanosilica on coating properties. Epoxy resin was selected as coating matrix and resole type phenolic resin was added as polymeric network modifier. After preparation of hybrid resin, the modified nanosilica was added in resin matrix in 1, 2 and 3 wt. %. Differential scanning calorimetric (DSC) was used for determination of the glass transition temperature (T_g) and curing heat of the coatings, scanning electron microscope (SEM) was employed for evaluation of nanosilica dispersion in the coatings. Finally, anticorrosion performance of the coatings was studied using electrochemical impedance spectroscopy (EIS), electrochemical noise measurement (ENM) and salt spray test. The DSC results illustrated that the coating containing phenolic resin has the lower T_g compared with the blank epoxy coating and incorporation of nanoparticles decreases the reaction heat of epoxy resin. In addition, the best anticorrosion performance was obtained for hybrid resin containing higher contents of nanosilica due to the steric hindrance of the nanoparticles and inhibition effects of resole resin.