Anticorrosive Epoxy Nanocomposite Coatings Filled with Polyaniline-Functionalized Silicon Nitride Particles
Hongfen Wang, Qi Qi, Yongxing Zhang, Shougang Chen, Binbin Dong, Shidong Zhu, Qian Hu, Zhanhu Guo
Abstract
Epoxy resin (ER) composite coatings on carbon steel were prepared with polyaniline (PANI)-functionalized silicon nitride (Si3N4) powders (PANI/Si3N4) as fillers. First, a 5% mass ratio of Si3N4 fillers for ER coatings was selected to achieve a better physical and anticorrosion performance of Si3N4/ER coatings than that of ER coatings. Then, to attain PANI/Si3N4/ER coatings, PANI coated Si3N4 fillers were prepared and added into the ER matrix at 5% mass ratio. The adhesion strength was further improved, and the water absorption rate was decreased for PANI/Si3N4/ER coatings compared to Si3N4/ER coatings. In electrochemical impedance spectroscopy tests, the resistance values of the PANI/Si3N4/ER coatings were all higher than those of Si3N4/ER coatings and ER coatings. All results revealed the excellent barrier effects of PANI-functionalized Si3N4 fillers and the significant roles of PANI in the prevention of coating elimination caused by interface defect sites. Finally, an anticorrosion mechanism of PANI/Si3N4/ER coatings was proposed.