S. Varvara
Sep 1, 2018
Citations
0
Influential Citations
2
Citations
Journal
International Journal of Electrochemical Science
Abstract
The inhibition proprieties of two phenothiazinyl-thiazolyl-hydrazine derivatives, namely ( E)-ethyl 2-(2-((10-ethyl-10H-phenothiazin-3-yl)methylene)hydrazinyl)thiazole-4-carboxylate (CxTP) and (E)-10-ethyl-3-((2-(4-phenyl thiazol-2-yl)hydrazono)methyl)-10H-phenothiazine (PhTP) on carbon steel corrosion in 1.0 M HCl solution were studied at various concentrations, temperatures and exposure times using electrochemical techniques, SEM-EDX and quantum chemical calculations. Potentiodynamic polarization revealed that the phenothiazinyl-thiazolyl-hydrazine derivatives act as mixed-type corrosion inhibitors; their inhibition efficiency increases with increasing the inhibitors concentration (91.6% at the optimal concentration of 150 µM for CxTP) and slightly decreases at elevated temperatures and after 24 hours exposure to the corrosive solution. Based on the electrochemical impedance spectroscopy results, two suitable structural models of the carbon steel/1.0 M HCl interface were proposed to describe the processes taking place in the absence and in the presence of the organic inhibitors, respectively. The adsorption of the organic inhibitors on carbon steel surface obey Langmuir isotherm. SEM-EDX investigations confirmed that the phenothiazinyl-thiazolyl-hydrazine derivatives are able to significantly retard the carbon steel dissolution. Density functional theory was used to understand the nature of the interactions between the protonated organic molecules and the metallic surface.