Comparison of corrosion protection of chemically and electrochemically synthesized poly(N-vinylcarbazole) and its nanocomposites on stainless steel

Abstract

Strong adherent electroactive polymer films of poly(vinylcarbazole) (PVCz) and its nanocomposites with P(VCz)/nanoclay and P(VCz)/Zn nanoparticle have been electrodeposited on stainless steel (SS304) by chronoamperometric method using 0.3 M oxalic acid/butanol solution. The corrosion protection performance of P(VCz), P(VCz)/nanoclay, and P(VCz)/Zn nanoparticle coating on stainless steel (SS304) was assessed in 3.5 % NaCl using potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) techniques. Open circuit potential (OCP) and polarization measurements have been shown that the SS304 coated with P(VCz), P(VCz)/nanoclay, and P(VCz)/nanoZn maintain the potential in the passive state whereas the uncoated SS304 exhibits potentials in the active state. The corrosion tests indicated that P(VCz), P(VCz)/nanoclay, and P(VCz)/nanoZn exhibited effective anodic protection in a corrosive test solution. Results show that chemically synthesized P(VCz), P(VCz)/nanoclay, and P(VCz)/nanoZn have higher corrosion performance (PE = 99.56, 98.10, and 98.97 %) than electrochemically synthesized films (PE = 94.87, 96.75, and 96.13 %). In addition, the highest protection efficiency was obtained as 99.56 % for chemically synthesized P(VCz) films. The protection efficiencies were calculated from corrosion currents obtained by Tafel extrapolation from polarization curves.