Synergistic effect of polyaniline grafted basalt plates for enhanced corrosion protective performance of epoxy coatings

Polyaniline-graft-basalt plates (PANI-g-BP) were prepared based on γ-aminopropyltriethoxysiliane (APTS)-modified basalt plates via in-situ chemical-oxidation polymerization method. Three PANI-g-BP samples were prepared by varying the ratio of aniline to BP, i.e. 1:2, 1:4, 1:6. The results of Fourier transformation infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermo gravimetric analysis (TGA) confirmed that PANI was successfully grafted on the surface of basalt plates. Different coatings were prepared by adding the synthesized PANI-g-BPs or PANI, and were coated on the mild steel subsequently. The water-uptake property, the adhesion strength and the passive properties of the coatings were investigated. In addition, the protective performance of the coatings was tested by the electrochemical impedance spectroscopy (EIS) in 12% NaCl solution at 95 °C. The results indicated that the coatings with 10% PANI-g-BP (1:4) exhibited the best protective performance and its impedance at 0.01 Hz is higher than 1010 after 80 days immersing.