Abstract
Mild steel (MS) is one among the extensively utilized materials in several industrial sectors, but prone to deterioration when exposed to acidic environment. The main focus of this study is to examine the corrosion inhibitive efficacy of 9-ethyl-3-carbazolecarboxaldehyde azine (CCA) on MS immersed in 0.5 M HCl medium. The corrosion inhibition efficiency of CCA which was investigated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques improved with rise in temperature and inhibitor concentration. CCA showed a maximum inhibition efficiency of 92.4% at 323 K for 5 × 10–5 M concentration in 0.5 M HCl medium. The variation in the kinetic and thermodynamic parameters indicated chemisorption of CCA on MS, and its mixed-type inhibitive action followed Langmuir’s isotherm model. The infrared spectra provided evidences for the chemical interaction of CCA with MS specimen. Surface morphology evaluation using SEM and AFM in combination with elemental analysis using an energy dispersive X-ray analyser (EDX) indicated the creation of a protective adsorption layer of CCA on MS surface. The quantum chemical investigations performed using density functional theory (DFT) computations supplemented the experimental results, suggesting the potential corrosion inhibition behavior of CCA toward MS in aggressive HCl medium.Graphic
Highlights
Mild steel renowned as low carbon steel is a majorly used material in construction, chemical and industrial sectors
We report the synthesis of a new azine wherein two molecules of 9-ethyl-3-carbazolecarbaldehyde molecules are linked through spacers carrying two nitrogen atoms and the exploration of its corrosion inhibition properties on Mild steel (MS) in Hydrochloric acid (HCl) environment
In the present study, we postulate that the incorporation of two aromatic carbazole rings with already proven anticorrosion behavior, in combination with two nitrogen atoms and –C=N– linkages incorporated into a single chemical skeleton can reinforce the inhibition efficiency of the proposed carbazolecarbaldehyde azine against MS exposed to HCl environment
Summary
Mild steel renowned as low carbon steel is a majorly used material in construction, chemical and industrial sectors. Organic small molecules which include more number of polar groups, heteroatoms, aromatic rings with π electrons and unsaturated bonds in their molecular structure are widely utilized as inhibitors in industrial sectors for various metals, especially MS because of their effectiveness in wide temperature ranges, material compatibility, good solubility, low costs and relatively low toxicity [5,6,7,8,9] These inhibitors can adsorb onto the material physically or chemically through electronic interactions to form protective film, which displace water and protect it from deterioration [10,11,12,13,14,15]. In the present study, we postulate that the incorporation of two aromatic carbazole rings with already proven anticorrosion behavior, in combination with two nitrogen atoms and –C=N– linkages incorporated into a single chemical skeleton can reinforce the inhibition efficiency of the proposed carbazolecarbaldehyde azine against MS exposed to HCl environment
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
