Mass transfer role in electropolishing of carbone steel in H3PO4 containing amino acids: Electrochemical, computational, SEM/EDX, and stylus profilometer investigation

The goal of this study is to look at the development and use of green inhibitors in the electropolishing process (EP), as well as their potential as an anti-corrosive coating for C-steel in an acidic medium. We can replace environmentally dangerous substances with inexpensive, effective molecules that have little or no negative environmental impact like amino acids which are employed as safe inhibitors. The EP characteristics of C-steel were measured by galvanostatic techniques with different concentrations of amino acids over a wide range of (1-1000 × 10−6 mol/l) and temperatures (298–313 K). The findings indicate that the electropolishing behavior of C-steel is governed by mass transfer, with Fe2+ being proposed as the governing species for the salt film mechanism during anodic dissolution in the limiting current plateau. The experimental results indicate that increases in the amino acid concentrations inhibit the EP by 83.33% in the case of L-Methionine at 298 K. Density Functional Theory (DFT) was used to optimize geometry in the gas and liquid phases. The inhibition efficiency was associated with global reactivity descriptors, Fukui indices and dual local descriptors. The inhibitory performance is in good agreement with the estimated quantum chemical parameters, according to our findings.