Synthesis of zinc modified poly(aniline-co-pyrrole) coatings and its anti-corrosive performance on low nickel stainless steel

Copolymer of poly(aniline-co-pyrrole) film was electrodeposited on low nickel stainless steel (LN SS) substrate from 0.1 M monomers (aniline and pyrrole) containing aqueous oxalic acid solution. The coatings were synthesized by means of cyclic voltammetric technique. Then, the polymer coatings were modified by depositing zinc particles over it by potentiodynamic cathodic sweeps. The corrosion performance of zinc modified poly(aniline-co-pyrrole) coatings was investigated in 1 M HCl solution, using potentiodynamic polarization and electrochemical impedance spectroscopic techniques. It was shown that the zinc modified poly(aniline-co-pyrrole) coatings exhibited a very low permeability and provided better corrosion protection to LN SS. This enhanced stability and better barrier properties may be due to the formation of pore free and adherent zinc modified poly(aniline-co-pyrrole) layer. Atomic force microscopy (AFM) and energy-dispersive X-ray analysis (EDAX) were used to study the morphology and coating composition of the LN SS specimen.