Corrosion inhibition of stainless steel by polyaniline, poly(2-chloroaniline), and poly(aniline- co-2-chloroaniline) in HCl

Abstract

Polyaniline (PANi), poly(2-chloroaniline) (PClANi), and poly(aniline- co-2-chloroaniline) ( co-PClANi) films were synthesized by electrochemical deposition on 304-stainless steel (SS) from an acetonitrile solution. The structural properties of these polymer films were characterized by spectroscopic (FTIR and UV–vis) and electrochemical (cyclic voltammetry) methods. Open circuit potential–time ( E ocp–time) curves, potentiodynamic polarization, and electrochemical impedance (EIS) measurements showed that these films have significant protective performance against corrosion of SS in 0.5 M HCl solution. It was found that co-PClANi film has acted as a passivator as well as barrier for cathodic reduction reaction in a similar manner as PANi film. However, PClANi film has behaved only as barrier for corrosion protection of SS in 0.5 M HCl.