Study the Effect of Different Parameters on the Corrosion and Inhibition Rate for Copper in Saline Solutions (original) (raw)
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Study of corrosion inhibition of copper in 0.1 M NaCl using the EQCM technique
Electrochimica Acta, 1998
The inhibition of Cu corrosion in 0.1 M NaCl solution was studied using the EQCM technique. Some organic compounds, at 10 À3 M concentration, were tested as inhibitors. The inhibiting eect of these additives was evaluated by recording the anodic and cathodic polarization curves on Cu, electroplated on quartz crystals. At the same time the mass changes of the electrode, as a function of the potential, were recorded. The formation of the protective ®lm during immersion in distilled water or 0.1 M NaCl solution containing the inhibitors was followed by variation of the EQCM frequency. The protective characteristics of these ®lms were evaluated by the mass variations of the electrode immersed in 0.1 M NaCl solution and by the voltammograms recorded after 1 min or 5 h immersion in 0.1 M NaCl solution. FTIR re¯ection spectra were recorded on Cu sheets immersed for 1 or 60 min in NaCl solution in the presence of inhibitors. They showed a very rapid interaction between metal surface and organic molecule. The results obtained allow us to conclude that EQCM technique has a valuable part to play in the interpretation of corrosion and corrosion inhibition mechanisms.
Corrosion and inhibition of copper in electrolyte solution
The inhibition action of p-chlorobenzohydroxamic acid (p-Cl-BHA) and dibenzylsulfoxide (DBSO) on copper corrosion in 0.5 M NaCl at pH6.5 and 0.1 M Na 2 SO 4 at pH3, respectively, were studied. The corrosion and inhibition processes were monitored by in-situ AFM, and morphological changes on the electrode surface were registered. The p-Cl-BHA greatly enhanced the resistance of copper to pitting corrosion in aqueous solution containing chloride ions. This effect is attributed to the formation of a continuous protective chemisorbed layer on the corroding metallic surface through which Cu 2 O will be stabilized. The DBSO, due to its adsorption and conversion to a more stable, less soluble sulfide compound, highly hindered copper corrosion in sulphate containing solutions.
Inhibition of copper corrosion in sodium nitrate solutions with nontoxic inhibitors
Corrosion Science, 2008
The influence of the concentration of purine (PU) and adenine (AD) on the corrosion and spontaneous dissolution of copper in 0.5 M NaNO 3 solutions of pH 3.0 was studied. The investigations involved electrochemical polarization methods and gravimetric measurements as well as quartz crystal microbalance (QCM) techniques and scanning microscopy (SEM). The inhibition efficiency increases with an increase in the concentration of PU and AD. Adherent layers of inhibitors were postulated to account for the protective effect. The adsorptions of inhibitors were found to occur on the surface of copper according to the Langmuir isotherm. The values of standard free energies of adsorption suggest the chemical adsorption of PU and AD on the copper surface.
Corrosion and inhibition of copper in different electrolyte solutions
Applied Physics A-materials Science & Processing, 1998
SO4 at pH≈3, respectively, were studied. The corrosion and inhibition processes were monitored by in-situ atomic force microscopy, and morphological changes on the electrode surface were registered. The p-Cl-BHA greatly enhanced the resistance of copper to pitting corrosion in an aqueous solution containing chloride ions. This effect is attributed to the formation of a continuous protective chemisorbed layer on the corroding metallic surface through which Cu2O will be stabilized. The DBSO, because of its adsorption and conversion to a more stable, less soluble sulphide compound, greatly hindered the copper corrosion in the sulphate-containing solutions.
Journal of Materials Science and Chemical Engineering
This work reports the inhibition properties of nicotinamide (NAM) for copper protection during its applications in seawater systems such as water pipelines, shipbuilding, seawater desalination and heat exchange systems. The efficiency of NAM as a copper corrosion inhibitor in simulated seawater (3.5% NaCl solution) was investigated by Tafel extrapolation and linear polarization methods in the temperature range from 20˚C to 50˚C. The corrosion parameters and the adsorption isotherms were determined using potentiodynamic polarization techniques. It was found that the inhibition efficiency (η) and the coverage rate (θ) increase up 80% at 25˚C for nicotinamide concentration of 10 mM but decrease as the temperature of the solution increases. Moreover, the obtained thermodynamic parameters using Langmuir model suggested a physical adsorption type. A correlation was found between the corrosion inhibition efficiency and the global theoretical parameters obtained by the functional density method B3LYP/ 6-31 + G (d, p). Local parameters such as condensed Fukui functions
Corrosion and inhibition studies of copper in aqueous solutions of formic acid and acetic acid
Corrosion Science, 1995
Corrosion behaviour of copper has been investigated in different compositions of formic acid and acetic acid at 30°C by a potentiostatic method. The maximum corrosion rate was found in 2&40mol/o formic acid and in 20 mol/o acetic acid in aqueous solution mixtures. The corrosion rate depended on the concentration of either acid. Formic acid is observed to be more corrosive than acetic acid. The metal exhibited active-passive behaviour in the concentration range of 30_70mol/o of HCOOH acid in the solution mixture. A short passivity range of potential with a high passivity current density was observed for the metal in the solution mixtures of HCOOH acid while in solution mixtures of acetic acid the metal exhibited only active dissolution. Some organometallic compounds, viz. BuzSnCIz, PhSnC13, Ph2SnC12, Ph3SnCI have been subjected to inhibition studies in the aqueous solution mixture (20 mol/o) of either acid. Among the inhibitors used Ph,SnCI functions as a better inhibitor in both acids. A strong interaction between the inhibitor and corroding surface of copper is speculated due to adsorption of the inhibitor.
Procedia Materials Science, 2015
Oxygen free copper is one of the candidate materials for the design of high level radioactive waste containers, due to its excellent resistance to generalized and localized corrosion in aqueous electrolytes; particularly in reducing environments as the ones expected in the repository site. The aim of this work is to contribute to determine the material durability from the corrosion point of view. To this purpose the anodic behavior of copper was studied in solutions with different electrolytes of interest for being present in groundwaters that might be in contact with the containers. The research program began with the study of corrosion susceptibility in chloride solutions, one of the main aggressive species to corrosion, and continued with the study of the behavior of copper in solutions with sulfate and bicarbonate, which are also present in the groundwaters that might be in contact with the repository. The corrosion potential was monitored and anodic polarization curves were performed varying the temperature and the concentration of ions in deaerated solutions of chloride, sulfate and bicarbonate. The study was complemented with microscopic observations of the corrosive attack and compositional determinations using Energy Dispersive Microanalysis (EDS). Preliminary results showed the aggressiveness of chloride ions: the corrosion potential decreased with the ion concentration and with temperature. The current density increased both with temperature and with chloride concentration. A breakdown potential was observed under certain conditions. Corrosion products showed a composition of 30 wt% Cl and 70 wt% Cu. In sulfate containing solutions, the corrosion potential decreased with temperature but increased slightly with the ion concentration, whereas the current density increased with temperature and it was not significantly affected by the concentration. A breakdown potential was identified, which decreased with temperature and increased with sulfate concentration. In bicarbonate containing solutions, the corrosion potential decreased clearly with temperature and slightly with concentration. Different characteristics
Synergistic effects in the inhibition of copper corrosion
Benzotriazole (BTA), thiourea (TU), and potassium ethylxanthate (KEX), behave as copper (Cu) corrosion inhibitors under certain conditions. These chemicals have been investigated to establish whether they provide synergistic effects. The Cu corrosion inhibition was followed through changes in electrochemical characteristics. Cu specimens were tested at 25°C in two aggressive media, 0.1 M NaCl and 1 M NaClO4, using the linear potential sweep technique at 0.001 V s–1 and by scanning electron microscopy of Cu specimens subjected to potentiodynamic and potentiostatic routines. A comparative behavior of the different substances for Cu was presented in the 6.6 < pH < 11 range. For KEX-BTA mixtures, synergistic inhibition effects were found in 0.1 M NaCl (7 < pH < 11). The apparent synergistic inhibition was explained tentatively by an increase in the compactness of the polymer-like passivating layer of KEX-Cu, which formed in the presence of BTA and Cl– ions.
Corrosion Inhibition of Copper in Acid Medium by Drugs: Experimental and Theoretical Approaches
2017
The inhibition performances of nafcillin (III), methicillin (II) and penicillin G (I) on the corrosion of copper in HCl was studied and tested by weight loss, Tafel polarization, SEM, UV-vis spectrophotometry, molecular dynamics method and quantum chemical calculations. Polarization curves indicated that the studied inhibitors act as mixed-type inhibitors. The values of inhibition efficiency and surface coverage were found to follow the order: Blank <penicillin <methicillin <nafcillin. The maximum inhibition efficiency of 98.28% was exhibited by nafcillin, and the minimum inhibition efficiency of 43.10% was showed by penicillin. The adsorption of inhibitors obeys the Temkin adsorption isotherm. The negative value of free energy of adsorption ∆Gads, indicated that the adsorption of three inhibitors was a spontaneous process. The SEM micrographs confirmed the protection of copper in a 1 M HCl solution by penicillin G, nafcillin, and methicillin. The shape of the UV/vis spectra of inhibitors in the presence of the immersion of Cu showed a strong support to the possibility of the chemisorbed layer formation on Cu surface by nafcillin (between nafcillin and Copper) and physisorption between penicillin and methicillin with copper. DFT calculations were performed to provide further insight into the inhibition efficiencies which were determined experimentally. Molecular dynamics (MD) simulations were applied to find the most stable configuration and adsorption energies of penicillin G, nafcillin and methicillin molecules on Cu (110) surface. The interaction energy followed the order: nafcillin (III)> methicillin (II)> penicillin G (I), which confirmed that nafcillin has the strongest interaction with the metal surface. The obtained results from experimental and theoretical methods were in reasonable agreement.
Sulfathiazole as potential corrosion inhibitor for copper in 0.1 M NaCl
Protection of Metals and Physical Chemistry of Surfaces, 2014
Effects of sulfathiazole (ST) on copper corrosion as a corrosion inhibitor in 0.1 M NaCl solutions have been studied using potentiodynamic polarization, open circuit potential, electrochemical impedance spectroscopy with scanning electron microscopy (SEM). Potentiodynamic polarization measurements indi cated that the presence of ST in chloride solutions affects mainly the cathodic process and decreases the cor rosion current and shifts the corrosion potential towards more negative values. The adsorption of inhibitor on the copper surface obeys the Langmuir adsorption isotherm. The adsorption free energy of ST on cop per (-33.47 kJ/mol) shows a strong adsorption of the inhibitor on the metal surface. The effect of tempera ture on the inhibition efficiency of sulfathiazole was examined with Arrhenius equation and activation ener gies in 0.1 M NaCl with and without inhibitor were calculated. Impedance data were analyzed using an appropriate equivalent circuit model for the electrode /electrolyte interface. SEM measurements also exhib ited that the ST molecules are strongly adsorbed on the copper surface.