Corrosion Inhibition Influence of the Synthetized Chromen-6-One Derivatives on Mild Steel in 1.0 M HCl Electrolyte: Electrochemical, Spectroscopic and Theoretical Investigations

In this work, two new chromen-6-one derivatives (BCC), namely 7-phenyl-6H,7H-benzo[f]chromeno[4,3-b] chromen-6-one (BCC-Ph) and 7-(furan-2-yl)-6H, 7H-benzo[f] chromeno [4,3-b] chromen-6-one (BCC-Fur), were prepared and identified by spectroscopic technique (NMR). Their performances inhibitions were assessed by electrochemical measurements, and they confirmed and explained using scanning electron microscope combined with energy dispersive X-ray spectroscopy (SEM/EDX) and theoretical studies (DFT calculation and MD simulation). Both electrochemical techniques revealed that the obtained performance value rises with the content of inhibitors to reach 94.94% and 83.57% at 10-3 M BCC-Ph and BCC-Fur, correspondingly. Moreover, according to the PDP method, these compounds behave as mixed-type inhibitors in 1.0 M HCl medium. In addition, the influence of temperature indicated that the performance of the chromen-6-one derivatives slightly decreases with the temperature, and they are characterized by the physico-chemical adsorptions process with chemical dominance, and they act according to the Langmuir approach. The SEM/EDX analysis revealed a significant reduction of the heterogeneity of the metal surface by the establishment of anti-corrosive layer. Finally, the DFT calculations and MD simulation explain the mode of the chromen-6-one derivatives molecules adsorption, and confirm the obtained experimental results

Structure – properties study of sodium bismuth borate glasses

Sodium bismuth borate glasses with composition (100–x)(0.785B2O3–0.215Bi2O3)–xNa2O where x=0, 2, 4, 6, and 8 mol%, were prepared by standard synthesized melt–quenching method. The amorphous and vitreous nature of these samples was confirmed by X–ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis. The density of the samples was measured using Archimedes principle and the molar volumes were determined from the density data. The spectroscopic properties of glass samples were studied using Fourier Transform Infrared Spectrometer (FTIR) and Raman spectroscopic techniques. The density of the samples was found to vary non–linearly with the Na2O content, however, a slight variation of the glass transition temperature was observed. The addition of Na2O in 78.5B2O3–21.5Bi2O3 glass causes changes in the features of the FTIR and Raman spectra. Both types of IR and Raman spectroscopic revealed that the network structure of the studied glasses is mainly based on BO3 and BO4 units, and bismuth exists as BiO3 pyramidal and BiO6 octahedral units

Green approach to corrosion inhibition of mild steel in 1 M HCl solutions by Monosaccharides derivatives

Effect of new synthesized monosaccharide derivatives, namely: D-mannose (M1), D-gluconic acid-γ-lactone (M2), D-galactono-γ-lactone (M3), monoacetoneglucose (M4), diacetoneglucose (M5), on mild steel corrosion inhibition in an aerated acidic solution of 1 M HCl was investigated using weight loss, potentiodynamic polarization curves, and electrochemical impedance spectroscopy measurements. The results indicate that the type of inhibition depends on the type of compounds. Impedance measurements showed that the charge transfer resistance increased and double layer capacitance values decreased with inhibitor’s concentration. It is seen that the M2 performed excellently as a corrosion inhibitor which its efficiency reaches 91 % at 10-3 M. Adsorption of M2 molecules on mild steel surface was also studied to examine basic information on the interaction between the inhibitors and the metal surface. It is found that the inhibitor adsorb on the metal surface following the Langmuir isotherm model. The temperature effect on the performance of mild steel in 1 M HCl in the absence and presence of the best compound was studied in the temperature range from 293 to 323 K. Also, some thermodynamic data for the adsorption and dissolution processes are calculated and discussed