Anti-H2S corrosion property of bipolar epoxy-resin coatings

Abstract

SiO2 nanoparticles were modified with the surfactants sodium dodecylbenzene sulfonate and hexadecyl trimethyl ammonium bromide. The modified SiO2 nanoparticles were added to epoxy-resin coatings to obtain anion- and cation-selective coatings. Two kinds of bipolar epoxy-resin coatings were prepared by exchanging the sequence of anion- or cation-selective coating (i.e., cation/anion and anion/cation). The coatings were immersed in H2S solution, and electrochemical impedance spectroscopy was used to investigate their performance. Scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to observe the morphology of the metals and metal/coating interface. Experimental results indicated that the coating sequence of inner and outer ion-selective coatings affected the protection performance of the bipolar coatings. The good protection property of the bipolar coatings was attributed to the existence of a space-charge region and an electric field between the inner and outer ion-selective coatings.