Abstract
Purpose - Archaeological bronze artefacts often are stored or displayed in uncontrolled conditions and may suffer from dangerous active corrosion processes that can lead to their destruction. The most dangerous form of archaeological bronze degradation is due to a cyclic reaction that involves copper from the pure alloy and chlorine as pathogenic agent. A protection treatment can be used to protect them from the corrosion environment and to stabilise them to avoid further degradation during exhibition or storage. Starting from its initial assessment as a corrosion inhibitor for pure copper, nowadays benzotriazole (BTA) is in widespread use for the conservation of copper-based artefacts, but unfortunately, BTA is toxic and a suspected carcinogen. The development of new and safe protection systems would offer a choice of alternative products to conservation-restoration professionals for the effective and safe stabilization and protection of metal artefacts. In this investigation, a new organic compound, namely 4-Amino-3-Methyl-1,2,4-Triazole-5-Thione (MTSNH), was synthesized, characterized and tested as a corrosion inhibitor for Bronze B66 (similar to archaeological bronze) in 3% NaCl solution, using potentiodynamic polarization studies and electrochemical impedance spectroscopy (EIS) at room temperature. It has been observed from the corrosion rate that the inhibition efficiency increased with increasing concentration of MTSNH. Potentiodynamic polarisation results revealed that the compound acted as mixed-type inhibitor. Impedance studies indicated that protection occurs through adsorption of the inhibitor on the metal surface, with important modification to the mechanism of corrosion. Surface analysis was carried out using SEM/EDX techniques to verify the electrochemical results. Design/methodology/approach - The inhibition efficiency of 4-Amino-3-Methyl-1,2,4-Triazole-5-Thione (MTSNH) is investigated by potentiodynamic polarization, impedance spectroscopy (EIS) and surface analysis. Findings - The synthesized MTSNH act a good inhibitor in 3% NaCl and inhibition efficiency increase with inhibitor concentration.Polarisation curves showd that the inhibitor is mixed. The impedance spectroscopy measurements showed that the inhibitor acted throught the formation of film at the Bronze surface. The surface analysis confirm this result. Originality/value - The adsorption of the MTSNH on the metal surface can markedly change the corrosion resisting property of metal. So the study of the relation between adsorption and corrosion inhibiting is of a great importance.
Purpose - Archaeological bronze artefacts often are stored or displayed in uncontrolled conditions and may suffer from dangerous active corrosion processes that can lead to their destruction. The most dangerous form of archaeological bronze degradation is due to a cyclic reaction that involves copper from the pure alloy and chlorine as pathogenic agent. A protection treatment can be used to protect them from the corrosion environment and to stabilise them to avoid further degradation during exhibition or storage. Starting from its initial assessment as a corrosion inhibitor for pure copper, nowadays benzotriazole (BTA) is in widespread use for the conservation of copper-based artefacts, but unfortunately, BTA is toxic and a suspected carcinogen. The development of new and safe protection systems would offer a choice of alternative products to conservation-restoration professionals for the effective and safe stabilization and protection of metal artefacts. In this investigation, a new organic compound, namely 4-Amino-3-Methyl-1,2,4-Triazole-5-Thione (MTSNH), was synthesized, characterized and tested as a corrosion inhibitor for Bronze B66 (similar to archaeological bronze) in 3% NaCl solution, using potentiodynamic polarization studies and electrochemical impedance spectroscopy (EIS) at room temperature. It has been observed from the corrosion rate that the inhibition efficiency increased with increasing concentration of MTSNH. Potentiodynamic polarisation results revealed that the compound acted as mixed-type inhibitor. Impedance studies indicated that protection occurs through adsorption of the inhibitor on the metal surface, with important modification to the mechanism of corrosion. Surface analysis was carried out using SEM/EDX techniques to verify the electrochemical results. Design/methodology/approach - The inhibition efficiency of 4-Amino-3-Methyl-1,2,4-Triazole-5-Thione (MTSNH) is investigated by potentiodynamic polarization, impedance spectroscopy (EIS) and surface analysis. Findings - The synthesized MTSNH act a good inhibitor in 3% NaCl and inhibition efficiency increase with inhibitor concentration.Polarisation curves showd that the inhibitor is mixed. The impedance spectroscopy measurements showed that the inhibitor acted throught the formation of film at the Bronze surface. The surface analysis confirm this result. Originality/value - The adsorption of the MTSNH on the metal surface can markedly change the corrosion resisting property of metal. So the study of the relation between adsorption and corrosion inhibiting is of a great importance.
