Copper Corrosion In Chloride Solutions Research Articles

Adsorption and inhibition study of N-(5-methoxy-2-hydroxybenzylidene) isonicotinohydrazide Schiff base on copper corrosion in 3.5% NaCl

Corrosion inhibition ability of synthesized Schiff base namely, N-(5-methoxy-2-hydroxybenzylidene) isonicotinohydrazide (NMHI) on copper in 3.5% NaCl solution was studied via electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP) and gravimetric study. Results showed NMHI to inhibit copper corrosion in chloride solution. The inhibition efficiency of NMHI was enhanced with an increase in the concentration but decreases with rising temperature. Maximum value of 97.7% inhibition efficiency was obtained with weight loss measurement at 303 K for the highest NMHI concentration (1 × 10-3 M) used. Polarization studies indicated that NMHI acted as mixed kind of inhibitor. The Nyquist plot revealed that double-layer capacitance (Cdl) declined and charge-transfer resistance (Rct) was enhanced with increase in NMHI concentrations, involving increased inhibition efficiency. NMHI adsorption onto the surface of copper obeyed Langmuir adsorption isotherm. Scanning electron microscopy (SEM) was used to characterize the morphology of uninhibited and inhibited copper surfaces.

Triazolyl-acylhydrazone derivatives as novel inhibitors for copper corrosion in chloride solutions

In this work, new designed triazolyl-acylhydrazone derivatives as inhibitors were developed to inhibit corrosion of copper in chloride solutions. Electrochemical techniques, morphological characterization, and measurements of contact angle, electrochemical quartz crystal microbalance and Fourier Transform Infrared Spectroscopy were combined to investigate the inhibition mechanism and performance. The high performance of the inhibitors is attributed to formation of inhibitor-adsorption films, which exhibit a hydrophobic property, and follow the Langmuir–Freundlich adsorbing isotherm model. Both chemisorption and physisorption occur simultaneously, however, the multi-dentate chemisorption of inhibitors on the copper surface plays the dominant role in corrosion inhibition.

The first X-ray photoelectron spectroscopy surface analysis of 4-methyl-2-phenyl-imidazole adsorbed on copper

4-Methyl-2-phenyl-imidazole is a new compound that can effectively inhibit copper corrosion in chloride solution.

Inhibition of copper corrosion in chloride solution by caffeine isolated from black tea

<p>Caffeine (1,3,7-trimethylxanthine) was isolated from black tea and characterized using different physical methods (determination of melting point, thin layer chromatography, FTIR spectroscopy and UV spectrophotometry). The corrosion inhibition performance of the caffeine isolate on copper corrosion in neutral 0.5 mol L-1 NaCl solution was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy measurements. The obtained results show that caffeine effectively inhibited the corrosion reaction in the chloride solution with inhibition efficiency up to » 92 %. Furthermore, caffeine was found to function essentially as a cathodic inhibitor by adsorption on the copper surface according to the Langmuir adsorption isotherm. The adsorption free energy of » –37 kJ mol<sup>-1</sup> indicates strong adsorption of the caffeine on the metal surface. Quantum chemical computations and molecular dynamics simulations were adapted to understudy the adsorption of a single caffeine molecule as well as a polymeric cluster of caffeine molecules on a model Cu surface at a molecular level and show good agreement with the experimental findings.</p>

Electrochemical adsorption properties and inhibition of copper corrosion in chloride solutions by ascorbic acid: experimental and theoretical investigation

In this study, the effect of ascorbic acid in the electrochemical behavior of copper has been investigated in 3.5 % NaCl solution using potentiodynamic polarization and electrochemical impedance spectroscopy. Current-potential curve and Nyquist diagrams were obtained in different concentrations of ascorbic acid. The surface morphology of copper after its exposure to 3.5 % NaCl solution with and without of ascorbic acid was examined by scanning electron microscopy. The obtained results show that ascorbic acid inhibits corrosion of copper in 3.5 % NaCl solution. The inhibition activity of ascorbic acid increases with a decrease in the concentration of ascorbic acid.

Inhibition of copper corrosion in chloride solutions by amino-mercapto-thiadiazol and methyl-mercapto-thiadiazol: an impedance spectroscopy and a quantum-chemical investigation

Inhibition of copper corrosion in chloride solutions by amino-mercapto-thiadiazol and methyl-mercapto-thiadiazol: an impedance spectroscopy and a quantum-chemical investigation

Inhibition of copper corrosion in chloride solutions by amino-mercapto-thiadiazol and methyl-mercapto-thiadiazol: an impedance spectroscopy and a quantum-chemical investigation

The efficiency of 2-amino-5-mercapto-1,3,4-thiadiazole and 2-methyl-5-mercapto-1,3,4-thiadiazole as copper corrosion inhibitors in neutral chloride environments was investigated. The study was carried out by means of a density-functional quantum-chemical approach and by impedance spectroscopy. The theoretical method was used to obtain a microscopic information about the surface–molecule interactions including the adsorption geometry conformations. Based on this information a physical model of the investigated system was proposed. A characteristic feature of it is the presence of interfacial phases between the bulk metal and the oxide and between the bulk oxide and the electrolyte. The derived model was relayed to an equivalent circuit which included the whole metal–oxide electrolyte system and the impedance data were fitted to it. The obtained estimates of the total dc path resistance showed that the studied thiadiazole derivatives were excellent copper corrosion inhibitors.

Tetrazole derivatives as corrosion inhibitors for copper in chloride solutions

The inhibiting action of some tetrazole derivatives on the copper corrosion in chloride solutions has been studied. Experiments have been carried on OFHC copper in 0.1 M NaCl solutions with the following tetrazole derivatives at the 10 −3 M concentration: tetrazole (T), 5-mercapto-1-methyl-tetrazole (5Mc-1Me-T), 5-mercapto(Na salt)-1-methyl-tetrazole (5NaMc-1Me-T), 5-mercapto-1-acetic acid(Na salt)-tetrazole (5Mc-1Ac-T), 5-mercapto-1-phenyl-tetrazole (5Mc-1Ph-T), 5-phenyl-tetrazole (5Ph-T) and 5-amino-tetrazole (5NH 2-T) in the range of pH from 4 to 8 and at temperatures of 40 and 80 °C. Some inhibitors have been studied from 10 −5 to 6 × 10 −3 M. Cathodic and anodic polarisation curves were recorded after 1 h of immersion. Polarisation resistances measurements have been made as a function of the time in the 300 h experiment. The weight loss measurements have confirmed the electrochemical trend. The prefilming action of some tetrazole derivatives has been evaluated. The interaction between the organic molecules and the metal surface has been studied by means of FTIR reflection spectra. All the inhibitors, except the 5Mc-1 Ac-T which stimulates the corrosion, show an inhibiting efficiency from 50 to 99%. In every case the inhibiting efficiency increases with increasing pH value. 5Mc-1Ph-T and 5Ph-T show the better protective characteristics.

Dithio‐oxamide as inhibitor of Copper corrosion in chloride solutions at various ph values

AbstractThis paper investigates the inhibiting properties of dithiooxamide (DTOA) towards copper corrosion in chloride media at different pH values. The aggressive solutions were prepared by dissolving 0.1 M sodium chloride in a Britton Robinson buffer, adjusted at the pH values of 3, 5, 7 and 9. The inhibitor was tested at the concentration of 10−3 M.The inhibiting efficiency of DTOA was evaluated after 20 days of immersion in the solutions at the temperature of 30°C. Both dc (polarization curves and voltammetric tests) and ac (electrochemical impedance spectroscopy, EIS) electrochemical tests were performed to elucidate the inhibition process.The results indicate that DTOA affords its best inhibiting efficiency at pH 5 and 7, but even at pH 3 it can retard the corrosion process. On the contrary, at pH 9 it stimulates the corrosion process. Between pH 3 and 7, the additive is reputed to form a protective film of Cu(II)DTOA salt, which is formed through a two step oxidative process, probably involving Cu(I)DTOA as an intermediate. The EIS analysis indicates that in chloride solutions copper fits a model of a partially blocked electrode. This analysis suggests that at pH 3 and 7 the film produced on copper by DTOA has a lower porosity than that of the oxide or cuprous chloride films formed in non inhibited solutions, thus hindering the mass transport through the layer.

Inhibition of copper corrosion in chloride solutions by heterocyclic compounds

AbstractFollowing a research programme on copper corrosion inhibition in neutral aqueous solutions, the present paper deals with the results obtained with some heterocyclic organic compounds as copper corrosion inhibitors in 0.1 NaCl solutions. The results are compared with those obtained with 1,2,3‐benzotriazole and 2‐benzothiazolethiol. The inhibiting action of the compounds mentioned has been determined by measuring corrosion rates and by tracing polarization curves. The characteristics of the surface layers have been investigated by recording the photopotentials by a pulse technique. The oscillographic recording of the sign, amplitude and time‐constant of the photopotentials has been obtained on electrodes in free corrosion conditions and during anodic and cathodic polarization. These measurements allow the determination of the semiconducting properties of the surface layers. Attentative is made to correlate the photopotentials data with the inhibiting efficiency of the compounds studied.