RESUMEN
The corrosion inhibition of (N 1 E)-N 1,N 2-bis(4-(dimethylamino)benzylidene)-ethane-1,2-diamine, DMAB, against the destruction of C-steel in dilute HCl media (1.0 M) was examined. The techniques of gravimetry, gasometry, potentiodynamic, and electrochemical impedance spectroscopy are utilized. The rate of corrosion is found to decrease with more additions of the DMAB compound. The inhibition efficacy increases with concentrations to reach 97.7% at 5.0 mM and 298 K. The protection of metal destruction is controlled by the adsorption of the DMAB molecules on the metallic surface obeying Langmuir's pattern. The computed ΔG°ads values are characterized by negative sign, explaining the spontaneity of the adsorption process. These values vary between -38.70 and -35.13 kJ mol-1 depending on the temperature, which proves the physio- and chemisorption mechanisms. The reduction in K ads values with T can be attributed to the desorption of some DMAB molecules from the electrode surface. Theoretical quantum computation confirms the adsorption of the DMAB compound in concurrence with the data obtained by practical techniques.
RESUMEN
The anticorrosion potency of two expired antifungal drugs, namely, bifonazole (BIF) and terconazole (TER), for X65 carbon steel (X65CS) in a 1.0 M HCl solution was estimated using practical and computational measurements. The results of all methods applied showed that the percentage of anticorrosive efficacy (% AE) increased for expired BIF and TER and reduced at elevated temperatures. The % AE values of expired BIF and TER (375 mg L-1) reached 92.08 and 94.19%, respectively, using polarization methods. The anticorrosion activities of the two expired drugs were interpreted based on their adsorption on the X65CS surface. The adsorption occurred according to the Langmuir isotherm model. The polarization results indicated that the expired drugs BIF and TER were mixed inhibitors. The impedance results showed a single capacitive loop, confirming that the charge transfer process controlled the corrosion of X65CS. Expired BIF and TER served as good pitting inhibitors by shifting the pitting potential to positive values. The thermodynamic functions of activation and adsorption were defined and explained. Density functional theory and Monte Carlo simulations were used to investigate the BIF and TER inhibitors. The theoretical parameters were consistent with the experimental results. The anticorrosion efficiencies determined using the various methods were in complete agreement.
RESUMEN
This research investigates the means to improve the compressive strength of mortar mixtures through using novel mixtures. These mixtures include magnetic water (MW) and fly ash (FA). MW was obtained by circulating tap water (TW) through a magnetic field. The magnetization duration was represented by the number of cycles, the content of FA was replaced with cement, and the super plasticizer percentage (SP) and the curing age were used and evaluated experimentally for producing the mortar mixtures. Mortar flow, crushing compressive strength, and ultrasonic pulse velocity (UPV) tests were applied to evaluate the performances of mixing characteristics. The results demonstrate that the MW-treated mortar mixtures show higher compression strength results than those prepared by TW. The compressive strength was increased up to 60% with 150 cycles, a dose of 0.5% of SP and no FA content at the age of 56 days. The dose of SP can be cut down by a maximum of 40% to 50% in cementitious mortar. the workability was enhanced by a percentage of 70%.
RESUMEN
Inhibition of the corrosion of carbon steel in hydrochloric acid solution by some mono- and bis-azo dyes based on 1,5-dihydroxynaphthalene was studied in relation to the concentration of inhibitors using weight loss and potentiostatic polarization techniques. The percentage inhibition efficiency calculated from two methods is in a good agreement with each other. The inhibition mechanism of the additives was ascribed to the formation of complex compound adsorbed on the metal surface. The adsorption process follows Freundlich adsorption isotherm. The formation of the complex compound was studied by conductometric and potentiometric titrations. The stability constants of the Fe-complexes were determined using the latter technique and related to the inhibition efficiency.