Synergistic Inhibition Effect of Sodium Silicate and Acrylamide on the Corrosion of Carbon Steel in a High-concentration KCI Solution

The corrosion inhibition performances of sodium silicate（Na2SiO3） and acrylamide（AM） for Q235 carbon steel in a high-concentration KCl solution（25%, mass fraction） were investigated via static mass loss method, elec- trochemical measurements, scanning electron microscopy（SEM）, X-ray photoelectron spectroscopy（XPS） and Auger electron spectroscopy（AES）. AM shows poor inhibition performance, while Na2SiO3 exhibits a better inhibition per- formance. Moreover, the steel gains mass instead of losing mass in the presence of 0.5% Na2SiO3 and 0.5% AM, in- dicating that the corrosion is completely inhibited~ SEM analysis indicates that a compact protective film is formed on the steel surface by the combined use of inhibitors. Our results demonstrate that Na2SiO3 and AM could have a synergistic effect on steel corrosion in high concentrations of KCl. The synergistic inhibition mechanism is further conjectured by the XPS and AES analysis.

Synergistic corrosion inhibition behavior of rare-earth cerium ions and serine on carbon steel in 3% NaCl solutions

The synergistic inhibition effect of CeCl3(Ce)and serine(Ser)on the corrosion of carbon steel in a 3%NaCl solution was investigated by electrochemical methods and surface analysis.The results showed that both CeCl3 and Ser,when used alone,had limited inhibition effect toward carbon steel corrosion in the 3%NaCl solution.In contrast,the combination of CeCl3 with Ser produced a strong synergistic effect on the corrosion inhibition behavior of carbon steel,improving the inhibition efficiency significantly.The polarization curves showed that the mixture of CeCl3 and Ser acts as a cationic-type inhibitor.Scanning electron microscopy and Fourier transform infrared spectroscopy showed that the synergistic inhibition effect was due to complex formation between the cerium ions and amino acid molecules.

Corrosion resistance of tannic acid,d-limonene and nano-ZrO_(2)modified epoxy coatings in acid corrosion environments

The protection of rusted carbon steel in acid corrosion environments is of great significance for equipment to keep safe operation.In this work,we presented a method to protect the rusted steel by ru st conversion treatment and epoxy coating.Tannic acid was selected as rust conversion agent.Tannic acid,D-limonene and nano-ZrO_(2)were used to improve the corrosion resistance of epoxy coatings.The Raman spectra,Xray diffraction and 3 D confocal images were used to characterize the rust conversion reaction.Ad hesion test showed that the loss of wet adhesion of the optimal coating was relatively low due to the addition of tannic acid,limonene and nano-ZrO(2).The corrosion resistance of five different coatings was investigated by scanning electron microscopy(SEM)and electrochemical analysis.Results show that after 264 h acid immersion,the low frequency resistance of the optimal coating consisting of rust conversion treatment and additives is 10^(7)Ωcm^(2),three orders magnitude higher than that of the pristine coating.Moreover,SEM indicates that the optimal coating possesses a smooth surface and an unbroken interface between substrate and coating.Accordingly,the corrosion-resistant mechanism of the hybrid coating is proposed.