Investigation of the effects of MoS2 doped (PANI and PPy) coatings on mild steel corrosion in alkaline medium

Abstract

One of the common ways of protecting the metal from corrosion is to form a film on the metal surface or coating it with a suitable material. Unfortunately, as long as there is a needle-like gap in the coating, water and oxygen will reach the metal surface and start corrosion. In this study polypyrrole (PPy), polyaniline (PANI), PPy + MoS2 and PANI + MoS2 coatings were obtained on steel in 0.1 M H2C2O4 by cyclic voltammetry method. The electro polymerization was carried out between 0.0 V and 1.0 V. The effect of these coatings on corrosion of steel was determined by the Tafel polarization method. As a result of experiments, it is determined that these obtained homogenous and adherent coatings are effective against corrosion. The best protection against corrosion is provided by PPy + MoS2, PPy, PANI + MoS2 and PANI coatings, respectively. Better protection efficiency of PPy than PANI can be explained by the fact that the pyrrole oxidation potential is lower than the oxidation potential of aniline. The reason MoS2 added coatings are more effective than others is that the gaps formed in the coating may be filled by MoS2.