Development of Mixed Metal Oxides–Conductive Polymer Composites for an Anticorrosive Application

The magnesium oxide–nickel oxide (MgO–NiO), nickel oxide–cobalt oxide (NiO–CoO), and magnesium oxide–cobalt oxide (MgO–CoO)-based mixed metal oxides (MMO) were synthesized by sol–gel method. The grafting of conductive polymers (CP), namely polyaniline (PANI), polyorthoanisidine (POA), and PANI–POA copolymer, is carried out on synthesized mixed metal oxide (MMO) by using a chemical oxidation method using ammonium persulfate (APS) as oxidizer, and the doping agent is used as hydrochloric acid (HCl) to make the MMO-CP composites. The synthesis of MMO-CP formation was confirmed with the FTIR, XRD, and UV–visible analysis. The epoxy-polyamide coating formulation is reinforced with MMO-CP composites at 4% (w/w) concentration, and the ultrasonication technique is used for uniform dispersion of MMO-CP into the coating formulation. The mild steel is used as a substrate for casting synthesized coating film, and curing is carried out at 90 °C. The mechanical analysis observed that hardness properties and scratch formation resistance are increased by reinforcement of MMO-CP, whereas chemical resistance remained unaffected. The corrosion resistance increased by incorporation of MMO-CP into the coating formulation, and it is evaluated by the salt spray analysis. The NiO–CoO–POA composite-based coating performs excellently in pencil hardness, scratch resistance, and in the salt spray test.