Adsorbed corrosion inhibitors studied by electron spectroscopy: Benzotriazole on copper and copper alloys (original) (raw)
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Copper is the only engineering metal that is noble metal. It resists many corrosive environments. But copper tarnish or corrodes under some circumstances. In recent years, investigators have shown that a system of tarnish or corrosion control for copper, brass and bronze can be built around the organic compound, 1, 2, 3, benzotriazole. Benzotriazole forms a strongly bonded chemisorbed two-dimensional barrier fi lm less than 50 angstroms thick. This insoluble fi lm, which may be a monomolecular layer, protects copper and its alloys in aqueous media, various atmospheres, lubricants, and hydraulic fl uids. Benzotriazole also forms insoluble precipitates with copper ions in solution (that is, it chelates these ion), thereby preventing the corrosion of aluminum and steel in other parts of a water system. J. B. Cotton. Imperial Metal Industries Ltd., Birmingham, England, has studied the tarnishing of copper and copper alloys exposed to humid environments, and the possibility of the prevention of staining by reaction with triazole type compounds. At the Second International Congress on Metal Corrosion, New York, 1963, he summarized the properties of commercially available benzotriazole and the reaction of this class of compound with copper ions. His report, "Control of Surface Reaction on Copper by Means of Organic Reagents", points out that the nitrogen-hydrogen group, and at least one of the other nitrogens in the ring, is involved in the complex bonding arrangements to copper. The polymeric chains or monomolecular plate-like complexes completely cover a clean metal surface, affording excellent protection. In the more typical case, benzotriazole probably plugs holes and defects in the copper oxide surfaces fi lm. Use of benzotriazole, and other protective chemicals such as tolutriazole, constitutes a signifi cant advance in the quest for corrosion inhibitors. It demonstrates that effective inhibition can function through the formation of true chemical bonds. The compound can also control the reaction between copper or copper alloy surfaces and typical environments. It is a useful additive to antifreeze and other water circulating systems; it can be incorporated into lacquers, protective wrapping papers, lubricants, hydraulic fl uids, and alkaline detergents. This data sheet reviews the literature and patents on the use of benzotriazole as a tarnish and corrosion inhibitor for copper and copper alloys it covers literature on the subject since 1957 in six application areas: Lacquers, Varnishes and Insulation, Storage and Packing, Lubricants and Sealants, Electrolytic Processes, Cleaning Solutions, and Water Systems. Laquers, Varnishes, and Insulation The natural color copper, its alloys and colored fi nishes applied by chemical treatment can be protected by a transparent lacquer inhibited with benzotriazole. Incralac, a fi nish developed by the copper industry, is an example. It is a transwww.copper.org
Comparison of a bio-based corrosion inhibitor versus benzotriazole on corroded copper surfaces
Corrosion Science, 2018
This research aims to characterize and compare the protective behaviour of a bio-based treatment versus benzotriazole (BTA) for the preservation of copper-based artefacts affected by active corrosion induced by copper chlorides. For this, the treatments were applied on artificial copper hydroxychlorides produced on copper sample. Their inhibition performance was then investigated by Scanning Electron Microscopy, Infrared Spectroscopy and Electrochemical Impedance Spectroscopy. Results showed few BTA-Cu complexes formed and poor protectiveness of the BTA treatments. In contrast, the bio-based treatment resulted in the conversion of almost all copper hydroxychlorides into copper oxalates, providing a more efficient corrosion inhibition.
A continuing challenge in materials design is the achievement of high operational efficiency through improvements in performance criterion, particularly its service life-time characteristics. Benzotriazole (BTAH) has now been in use for many years for the protection of copper and copper alloys against various forms of corrosion. In this review, the chemistry of BTAH and theories regarding its mode of action are summarized. Also, a survey of the reported work in both clean and polluted environments is documented. More interestingly, the adverse effect of BTAH on the corrosion of Cu and Cu alloys in sulfide polluted environments is introduced.
The inhibition of copper corrosion by Benzotriazole (BTA) in 5% HCl has been investigated by weight loss technique at different temperatures. Langmuir adsorption isotherm, Freundlich Adsorption Isotherm and Kinetic-Thermodynamic Model were used to describe the adsorption process depending on values of surface converge. Maximum value of surface converge was 0.998 for BTA at 35 oC and 15 g/l inhibitor concentration, while the lower value was 0.868 at 55 oC and 1 g/l inhibitor concentration. The films formed on the copper-nickel alloy surface of BTA appeared to obey the Langmuir Adsorption Isotherm more than Freundlich adsorption isotherm. In the other hand, results showed that the Kinetic-Thermodynamic Model was unsuitable to fit the experimental data of the BTA of the present study.
The effect of 1H-benzotriazole (BTAH) with ppm (part per million) grade concentrations on copper corrosion in aerated 3 wt. % NaCl solution is studied using chemical method (weight loss) and electrochemical methods (Potentiodynamic Polarization and Electrochemical Impedance Spectroscopy (EIS)). The present study confirm that the BTAH acts as a mixed-type inhibitor of copper corrosion in 3 wt. % NaCl. The optimum inhibition efficiency is at 30 ppm of BTAH. The surface characterization is performed using Scanning Electron Microscopy (SEM) to confirm the adsorption of the inhibitor molecules after 21 days of immersion time in aerated 3 wt. % NaCl. The results obtained from different techniques used in this research are in very good agreement and revealed that the BTAH is a very good inhibitor of copper corrosion in sodium chloride medium. Computer Simulation techniques confirm that the BTAH molecules adsorbed on the Cu (110) Surface.
Journal of Applied Electrochemistry, 2010
Copper corrosion inhibition in 1 M HNO 3 solution by some benzotriazole derivatives, namely N-(2-thiazolyl)-1H-benzotriazole-1-carbothioamide (TBC), N-(furan-2ylmethyl)-1H-benzotriazole-1-carbothioamide (FBC) and N-benzyl-1H-benzotriazole-1-carbothioamide (BBC), was investigated by ac impedance, dc polarization and weight loss techniques. A significant decrease in the corrosion rate of copper was observed in presence of the investigated compounds. The corrosion rate was found to depend on the concentration and type of the inhibitor. The degree of surface coverage of the adsorbed inhibitor was determined by weight loss technique, and it was found that the results obeyed Langmuir adsorption isotherm. Tafel polarization data indicated that the three selected inhibitors were of mixed type. The reactivities of the compounds under investigation were analyzed through Fukui indices, derived from density functional theory (DFT), to explain their inhibition performance.
With contrast to the traditional techniques of identifying and synthesizing new corrosion inhibitors in wet lab, a prior dry-lab process, followed by a wet-lab process is suggested by using cheminformatics tools. Quantum chemical method is used to explore the relationship between the inhibitor molecular properties and its inhibition efficiency. The density function theory (DFT) is also used to study the structural properties of three selected benzotriazole derivatives namely, benzotriazole-1-carboxamide (BCA), 1H-benzotriazole-1-acetonitrile (BAN) and benzotriazole-1-carbonyl chloride (BCC) in aqueous phase. It is found that when the benzotriazole derivatives adsorb on the copper surface, molecular structure influences their interaction mechanism. The inhibition efficiencies of these compounds showed a certain relationship to highest occupied molecular orbital (HOMO) energy, Mulliken atomic charges and Fukui indices. A wet lab study has been carried out using weight loss, Tafel polarization and impedance measurements to evaluate their inhibition performance in 1.0 M HNO 3 solutions at 25°C. Adsorption takes place by a direct chemisorption on the exposed copper surface, while it most probably occurs via hydrogen bonding on the oxidized surface. BCA was the most effective among the tested inhibitors, while BCC was less effective than BAN. Results obtained from dry-lab process are in good agreement with those recorded from wet-lab experiments.
An Extraordinary Effect of Benzotriazole and Sulfide Ions on the Corrosion of Copper
Electrochemical and Solid State Letters, 2006
While benzotriazole ͑BTAH͒ is an excellent inhibitor for the corrosion of copper in unpolluted media, it promotes corrosion in sulfide-polluted salt water. BTAH looses its remarkable inhibiting efficiency in the unpolluted medium and allows corrosion rates that are greater than those in the absence of BTAH. Scanning electron microscopy images revealed extensive general corrosion. On the other hand BTAH inhibited the anodic dissolution of copper at more noble potentials in the polluted medium. The results are discussed in terms of competition between the sulfide ions and BTAH for adsorption on the surface and for complex formation with copper ions.