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The effect of the addition of the oxo-anions , and of the cations Ce3+, Ce4+, Li+ and Mg2+ on the corrosion behaviour of the Al 3003 and Al 6063 alloys in carbonate solution is studied by electrochemical polarisation methods. The results show that these ions is the best inhibitor of Al 3003 alloy but only Ce3+ and Ce4+ are inhibitors for Al 6063 alloy. The inhibition efficiencies (IE%) of the , Ce3+, Ce4+ and Mg2+ reached 90% at 10-2M for Al 3003 alloy but of Ce3+, Ce4+ is 50% at 10-2M for Al 6063 alloy. Tafel lines of Al 6063 and Al 3003 alloys do not change with increasing of temperature in the presence and absence inhibitors. The IE% of Al 3003 of , Ce3+, Ce4+ and Mg2+ is temperature independent. The increase of IE% of Li+ from 76 to 99.6% at 25 and 70°C, respectively, illustrates the performance of this inhibitor at elevated temperatures for Al 3003 alloy. [Copyright &y& Elsevier]

Some inorganic compounds have been tested as corrosion inhibitors for 6063 aluminium alloy in 3% NaCl by electrochemical and metalographic methods. The compounds were MoO[sub 4] [sup 2–] , CrO[sub 4] [sup 2–] , NO[sub 2] [sup –] oxo-anions and Li[sup +] and Mg[sup 2+] metallic cations. Results obtained show that these compounds inhibited corrosion of 6063 aluminium alloy, and that the Li[sup +] cations were the best inhibitors. The difference between pitting potential and corrosion potential increase by increasing the concentration of Li[sup +] . The maximum inhibition efficiency (E% = 85%) was attained at 5 × 10[sup –3] M. Increasing temperature from 25 to 55°C improve corrosion resistance of 6063 aluminium alloy in the absence of Li[sup +] . However, in the presence of these cations, E% decreased at elevated temperature.Key words: corrosion, inhibition, inorganic compounds, 6063 aluminium alloy, 3% NaCl.L'effet de l'addition de certains composés inorganiques sur le comportement à la corrosion d'un alliage d'aluminium 6063, dans une solution de chlorure de sodium à 3 % est étudié à l'aide des méthodes électrochimique et métallographique. Les composés testés sont les oxo-anions MoO[sub 4] [sup 2–] , CrO[sub 4] [sup 2–] , NO[sub 2] [sup –] et les cations métalliques Li[sup +] et Mg[sup 2+] . Les résultats obtenus montrent que les composés testés inhibent le processus de corrosion de l'alliage 6063. Le caractère inhibiteur le plus marqué est obtenu en présence des ions Li[sup +] . L'augmentation de la concentration de ces ions a pour effet d'accroître la différence entre le potentiel de piqûration et le potentiel de corrosion. L'efficacité maximale de l'ordre de 85 % est atteinte dès une concentration de 5 × 10[sup –3] M. L'élévation de la température de 25 à 55°C a pour effet d'améliorer la résistance à la corrosion de l'alliage 6063 dans le milieu témoin. Cependant, en présence des ions Li[sup +] , l'efficacité inhibitrice subit une décroissance lorsque la température augmente.Mots clés : corrosion, inhibition, composés inorganiques, alliage d'aluminium 6063, NaCl 3 %. [ABSTRACT FROM AUTHOR]

Abstract: The inhibition effect of five amino acids (AA) on the corrosion of copper in molar nitric solution was studied by using weight loss and electrochemical polarization measurements. Valine (Val) and Glycine (Gly) accelerate the corrosion process; but Arginine (Arg), Lysine (Lys) and Cysteine (Cys) inhibit the corrosion phenomenon. Cysteine is the best inhibitor. Its efficiency increases with the concentration to attain 61% at 10−3 M. Correlation between the quantum chemical calculations and inhibition efficiency was discussed using semi-empirical methods (AM1 and MNDO). [Copyright &y& Elsevier]

Abstract The study of the inhibitory power of the Pulp of Jujube (PJ) extract of the plant Zizyphus Lotus with respect to the corrosion of copper in 1 M hydrochloric medium has been realized. This study was conducted by stationary and transients electrochemical measurements, weight loss and atomic absorption spectroscopy techniques. Scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), Fourier transform infrared (FT-IR) and atomic force microscopy (AFM) studies were used to characterize the surface of uninhibited and inhibited copper specimens. The results showed that the inhibition increases with PJ extract concentration reaching a maximum of 93% at a concentration of 1 g L−1. The obtained results indicate that PJ extract can act as a good green corrosion inhibitor for copper in 1 M HCl. The effect of temperature was also investigated and thermodynamic parameters were determined and discussed. Graphical abstract Unlabelled Image Highlights • The PJ extract is highly efficient corrosion inhibitor. • The inhibitory efficiency reaches a value of 93% at 1 g L−1. • Polarization studies revealed that PJ acts as a cathodic type. • The temperature effect revealed that the mode of adsorption is a physical nature. • The inhibition mechanism is studied using SEM/EDS, AFM and FT-IR surface analysis. [ABSTRACT FROM AUTHOR]

The anti-corrosion behavior of sodium alginate (SA) on copper in the 1 M hydrochloric medium was carried out using weight loss and electrochemical measurements. The obtained results show that the inhibition increases with SA concentration and then reaches a maximum of 83% at a concentration of 0.1 mg L − 1 . The effect of temperature on the reactions of copper corrosion inhibition and analyzing the thermodynamic parameters revealed that the mode of adsorption has a physical nature and obeys the Langmuir isotherm. The surface morphology was performed by scanning electron microscopy coupled with energy dispersive X-ray spectrometry and atomic force microscopy. To better understand the adsorption mechanism, describing the relationship between inhibitory ability and the molecular structure of SA, quantum calculations using density functional theory were performed. Monte Carlo simulation approache was performed to know well of the relationship between the inhibition ability and molecular structure of alginate. [ABSTRACT FROM AUTHOR]

An effective and eco-friendly Jujube shell (JS) extract was studied as a corrosion inhibitor for copper in 1 M hydrochloric acid. This work was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and weight loss coupled with atomic absorption spectroscopy techniques. Atomic force microscopy (AFM), Scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS) revealed the surface morphology in the presence and absence of inhibitor on the metal surface. The experimental results reveal that the JS extract act as a cathodic-type with an inhibition efficiency (IE%) up to 91% for 2 g L−1 at 298 K. In addition, this extract shows good inhibitory activity at a wide range of temperatures. The thermodynamic parameters were determined and discussed. Meanwhile, Monte Carlo simulation and Quantum chemical calculations by application of density functional theory (DFT) were carried out to help better understand the inhibition mechanism of this extract on the copper surface. The results indicated the feasibility of using the Jujube shell (JS) extract as a corrosion inhibitor in acid environment. Unlabelled Image • The inhibitory efficiency reaches a value of 91% at 1 g/L. • Polarization studies revealed that JS acts as a cathodic type. • The JS extract is highly efficient corrosion inhibitor. • The inhibition mechanism is studied using SEM/EDS and AFM surface analysis. [ABSTRACT FROM AUTHOR]