The current study investigates the improvement in the corrosion protection performance of C‐steel after being dip‐coated with nano films from both pure TiO2 and poly ethylene glycol (PEG) modified TiO2. Characterization of the deposited TiO2 films was performed by different techniques. Effect of morphology, porosity, and thickness of the deposited TiO2 layers were also studied. Results revealed an increased corrosion protection of both coated TiO2 films as compared to uncoated samples, with pure TiO2 (without PEG) samples showing higher protection. Moreover, increasing the layer thickness of both types of TiO2 coated films improved the protective properties.

Novel quaternary ammonium surfactants based on imines, namely, (E)-3-((2-chlorobenzylidene)amino)-N-(2-(decyloxy)-2-oxoethyl)-N,N-dimethylpropan-1-aminium chloride, (ICS-10) and (E)-3-((2-chlorobenzylidene)amino)-N,N-dimethyl-N-(2-oxo-2-(tetradecyloxy)ethyl)propan-1-aminium chloride (ICS-14) were synthesized and their chemical structures were determined by different spectroscopic approaches. The surface properties of the target-prepared surfactants were investigated. The effects of both synthesized imine surfactants on carbon-steel corrosion in 1.0 M HCl solution were investigated by weight loss (WL), potentiodynamic polarization (PDP), and scanning electron microscopy (SEM) methods. The outcomes show that the inhibition effectiveness rises with raising the concentration and diminishes with raising the temperature. The inhibition efficiency of 91.53 and 94.58% were attained in the optimum concentration of 0.5 mM of ICS-10 and ICS-14, respectively. The activation energy (Ea) and heat of adsorption (Qads) were calculated and explained. Also, the synthesized compounds were investigated using density functional theory (DFT). Monte Carlo (MC) simulation was utilized to understand the mechanism of adsorption of inhibitors on the Fe (110) surface.

Novel surfactants were synthesized based on cottonseed oil and diethanolamine and the structures of these compounds were confirmed by FTIR spectroscopy. The surface and thermodynamic properties of these compounds have been investigated. The corrosion behavior of the synthesized surfactant corrosion inhibitors was evaluated by using potentiodynamic (Tafel) polarization curves, linear polarization resistance corrosion rate techniques. The experimental results showed that these inhibitors revealed a very good corrosion inhibition even at low concentrations. The protection efficiency increased with increasing inhibitor concentration, getting maximum values ranged between 87.37 and 97.91 % at 100 ppm after 20 hour of exposure. The adsorption process was found to obey the Langmuir adsorption isotherm.

An effective and accessible synthesis of alkoxy arylnicotinonitriles was achieved via a four-component reaction of 4-hydroxybenzaldehyde, acetophenones, malononitrile in the presence of RONa. The synthesized alkoxy arylnicotinonitrile derivatives containing pyridine moiety were predestined as inhibitors for C1018-steel (CS) corrosion in 1.0 M HCl using potentiodynamic-polarization (PDP) and electrochemical impedance spectroscopy (EIS) methods. PDP plots were demonstrated that the arylnicotinonitriles behave as typical inhibitors of the mixed-type. They have also suppressed the CS corrosion at lower [inhibitor] and accomplished an inhibition capacity ranged from 87.6 to 98.2% in 0.7 mM. Their adsorption on the CS interface follows the isotherm model of Langmuir and they include both chemisorption and physisorption mechanisms, with a preference of chemisorption. The morphology of the CS surface was examined utilizing Fourier Transform Infrared Spectroscopy (FTIR) and field-emission scanning electron microscopy (FE-SEM). Moreover, Density Functional Theory (DFT) calculations confirm the empirical findings and the adsorption of arylnicotinonitrile derivatives on the CS interface.

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