Electro Polymerization of Polypyrrole Coatings Doped with Different Proton Acids for Corrosion Protection of 304 Stainless Steel

Abstract

Abstract. Polypyrrole (PPY) coatings doped with sulphuric, oxalic and phosphoric acid were prepared on 304 stainless steel (304SS) by electropolymerization. Surface morphology and anti-corrosive performance of the polymer film was investigated by scanning electron microscope and electrochemical tests. The results indicate that the phosphoric acid doped PPY coating has a compact and smooth surface which shifts the Ecorr of 304SS towards to more positive value, while the jcorr was dropped from 10.4 to 0.88 μA cm -2 . Long-term immersion test shows that the PPY coating doped with phosphoric acid provides better and durable corrosion resistance in comparison with the PPY coatings doped with the sulphuric and oxalic acids.

Experimental and Theoretical Studies on the Corrosion Inhibition of Carbon Steel by Two Indazole Derivatives in HCl Medium

“…The relevant data (in Table 2) are obtained by the extrapolation method. The inhibition efficiency η P is calculated by the following equation [22,23,24]:ηp=false(icorr0−icorricorr0false)×100 where i 0 corr and i corr are the corrosion current density in 1 M HCl solutions without and with the two investigated inhibitors, respectively.…”

Electrosynthesis of a Duplex Coating Consisting of a Cerium-Based Layer and a Polypyrrole Film for the Corrosion Protection of AISI 304 Stainless Steel

“…Among these polymers, polypyrrole (PPy) has been extensively investigated due to its physicochemical stability, high conductivity, easy processability and relatively low cost [9]. Several studies have reported that the electrosynthesis of polypyrrole (PPy) films on pure iron [10,11], mild steel [12][13][14] and stainless steel [15][16][17][18] can effectively inhibit the corrosion of these materials. It has been proposed that PPy coatings protect metallic substrates through a mixed mechanism of isolation and charge transfer [18].…”