3,4-Dimethoxy phenyl thiosemicarbazone as an effective corrosion inhibitor of copper under acidic solution: comprehensive experimental, characterization and theoretical investigations

This study investigates the corrosion inhibition potential of 3,4-dimethoxy phenyl thiosemicarbazone (DMPTS) for copper in 1 M hydrochloric acid (HCl) solutions, aiming to disclose the mechanism behind its protective action. Through an integrative methodology encompassing electrochemical analyses-such as weight loss measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS)-we quantitatively evaluate the corrosion protection efficacy of DMPTS. It was determined that the optimal concentration of DMPTS markedly boosts the corrosion resistance of copper, achieving an impressive inhibition efficiency of up to 89% at 400 ppm. The formation of a protective layer on the copper surface, a critical aspect of DMPTS's inhibitory action, was characterized using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). These techniques provided empirical evidence of surface morphology modifications and roughness changes, affirming the formation of a protective barrier against corrosion. A significant advancement in our study was the application of Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy, which identified chemical adsorption as the definitive mechanism of corrosion inhibition by DMPTS. The ATR-FTIR results explicitly demonstrated the specific interactions between DMPTS molecules and the copper surface, indicative of a robust protective adsorbed layer formation. This mechanistic insight, crucial to understanding the inhibitory process, aligns with the protective efficacy observed in electrochemical and surface analyses. Theoretical support, provided by the Quantum Theory of Atoms in Molecules (QTAIM) and quantum chemical computations, further validated the strong molecular interaction between DMPTS and copper, corroborating the experimental findings. Collectively, this research not only confirms the superior corrosion inhibition performance of DMPTS in an acidic setting but also elucidates the chemical adsorption mechanism as the foundation of its action, offering valuable insights for the development of effective corrosion inhibitors in industrial applications.

The curious case of polyphenols as green corrosion inhibitors: a review on their extraction, design, and applications

Over the past century, a substantial amount of research focused on developing corrosion inhibitors, with a special focus on green "plant-based" corrosion inhibitors. Among the various types of inhibitors, polyphenols emerged as a promising candidate due to their advantageous characteristics, which include being inexpensive, biodegradable, renewable, and, most importantly, safe for both the environment and humans. Their performance as sustainable corrosion inhibitors have encouraged many electrochemical experiments as well as theoretical, mechanistic, and computational studies, with many papers reporting inhibition efficiencies of over 85%. In this review, the majority of literature contributions on the inhibition of various types of polyphenols, their natural extraction techniques, and their applications as "greener" corrosion inhibitors for metals are thoroughly described and discussed with a focus on their preparation, inhibition mechanism, and performance. Based on the reviewed literature, it can be concluded that polyphenols have a very promising potential to be used as both green and powerful corrosion inhibitors; therefore, further investigations, experimental or computational, are still required to realize higher inhibition efficiencies reaching up to ≈ 100%.

Corrosion protection performance of silicon-based coatings on carbon steel in NaCl solution: a theoretical and experimental assessment of the effect of plasma-enhanced chemical vapor deposition pretreatment

Using a plasma-assisted chemical vapor deposition (PACVD) process, carbon steel samples were coated with an organosilicon layer less than 2.5 microns thick. Ellipsometry, Fourier transform infrared (FTIR) spectroscopy, contact angle, scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to analyze the films. Additionally, gravimetric experiments were used to determine the electrochemical properties of the organosilicon coatings. Organosilicon-coated carbon steel specimens demonstrated significantly enhanced resistance to corrosive conditions, such as 3% aqueous sodium chloride solutions. The surface preparation method has a considerable influence on the morphological and electrochemical properties of the steel. Argon pretreatment significantly enhances the corrosion resistance of organosilicon-coated steel. Gravimetric research demonstrated that pretreatment with argon plasma resulted in less weight loss and corrosion than pretreatment with nitrogen plasma. The link between quantum computing and experimental data using density functional theory (DFT) and molecular dynamics (MD) was used.