Phosphate-doped polyaniline/Al₂O₃ nanocomposite coating for protection of stainless steel

Abstract

Purpose This work aims to prepare and characterize of protective anticorrosion phosphate-doped polyaniline (PANI) nanocomposite coatings for stainless steel (SS) in chloride solution. Design/methodology/approach PANI composite coatings were electrodeposited from aqueous sulfuric acid solution containing monomer and Al2O3 nanoparticles using cyclic voltammetry technique. Doping by phosphate was done by aging the coated steels for different periods (1–168 h) in phosphate solution. The polymer film composite was investigated by Fourier-transform infrared spectroscopy and scanning electron microscopy techniques. Potential-time, anodic polarization and electrochemical impedance spectroscopy were used to study the protection efficiency of the coatings. Findings The Al2O3 nanoparticles were incorporated into the deposited PANI layer but they decreased the deposition of polymer. The nanoparticles and the phosphate anions enhanced the protective PANI layer for passivation and protection of SS in the chloride solution. Originality/value The replacement of counter anions by phosphate ions improved significantly the PANI and its nanocomposite as protective coating of SS in chloride solution.

Recent progress of self-healing polyaniline organic composite coatings: active agents, methods and protection mechanism

“…Comparatively, PANI is commonly doped with organic phosphorus acids, sulfonates, tungstates, molybdates and dioctyl phosphate salts. These composite coatings exhibit self-healing ability properties and offer active protection for carbon steel (Plesu et al, 2006;Sathiyanarayanan et al, 2010;Kamaraj et al, 2011;Samui and Phadnis, 2005;Karpakam et al, 2011;Hermas et al, 2020). Dodecylbenzene sulfonic acids sodium dodecyl sulfate, lignosulfonate, camphorsulfonic acid, sulfosalicylic acid and p-toluene-sulfonic acid are used as doping agents of PANI to provide active protection for Al alloys (Ogurtsov et al, 2004;Gupta et al, 2013;Ding et al, 2021;Du et al, 2018;Liu et al, 2022a).…”

Nanoparticle and Schiff Base Compound in Poly(O-Aminobenzyl Alcohol) Coating for Protection of 316L Stainless Steel against Corrosion

“…Moreover, the suggestion of an acceptable conductive polymer coating for a particular system is a difficult and important process because the efficiency of organic coating and the protection time is fairly limited and violently attributed to the corrosive medium. To improve their protection efficiencies and to prepare better quality coatings, their possible uses as a top or primer coatings or as blends have been investigated by many scientists [38][39][40][41][42][43]. Schiff bases derived from a carbonyl and an amino compound have been extensively studied to improve the anticorrosive properties of metals through the coordination of azomethine nitrogen to metal ions.…”