Multi-criteria evaluation of self-protecting waterborne coating based on mesoporous silica nanoparticles in corrosion environment

摘要

The self-protecting composite system, which is proposed in this paper, consists of encapsulated corrosion inhibitor that is dispersed within a waterborne coating. The mesoporous silica nanoparticles served as a host for two different corrosion inhibitors, 8-Hydroxyquinoline and 1-hydroxybenzotriazole. Such nanoparticle composites were embedded in the waterborne epoxy coating in two different concentrations and applied to the steel test substrates. The concentrations of nanoparticles in the final cured coatings were calculated to be 0.69 wt% and 0.35 wt% for each inhibitor. Electrochemical impedance spectroscopy, open circuit potential measurement, humidity chamber and salt spray chamber testing followed by adhesion testing were used to investigate the protective properties of the composite coatings. Results showed higher corrosion resistance of the coatings embedded with the nanoparticles containing inhibitors, in comparison with the coating without nanoparticles. Release of the inhibitor from nanoparticles in response to corrosion damage were recorded during immersion in the NaCl media. Samples containing 1-hydroxybenzotriazole showed the best corrosion resistance properties during the test period. The percentage loss of adhesion properties after humidity chamber testing is similar for all samples but is more pronounced for samples containing nanoparticles after salt spray chamber testing.