Faculty Publications
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Item The corrosion behavior of AZ31 alloy in chloride and sulfate media – A comparative study through electrochemical investigations(National Engg. Reaserch Center for Magnesium Alloys zhangdingfei@cqu.edu.cn, 2019) Acharya, M.; Nityananda Shetty, A.N.The magnesium alloys are considered to be the best structural materials, because of their advantageous weight to strength ratio. But, the limitation in their real field applications lies on the fact that magnesium alloys are highly susceptible for corrosion. The corrosion behaviour of AZ31 alloy was investigated by electrochemical methods in sodium chloride and sodium sulphate of different concentrations at different temperatures. The corrosion rate was monitored by potentiodynamic polarization technique and electrochemical impedance spectroscopy method. The surface morphology and surface composition of the freshly polished surface of the alloy was compared with that of the corroded surface by recording their SEM images and EDS, respectively. The results showed that the corrosion rate of AZ31 alloy increased with the increase in the temperature of the medium and also with the increase in the salt concentration of the medium. The activation parameters for the corrosion process were calculated and interpreted. © 2019Item Experimental and Theoretical Studies on an Anionic Gemini Surfactant as Corrosion Inhibitor for AZ31 Magnesium Alloy(Springer Science and Business Media Deutschland GmbH, 2022) Acharya, M.G.; Nityananda Shetty, A.N.Abstract: Sodium 2,2′-(13,22-dimethyl-14,21-dioxo-13,16,19,22-tetraazatetratriacontane-16,19-diyl)diacetate anionic Gemini surfactant was synthesized and utilized as a corrosion inhibitor for AZ31 alloy. The corrosion inhibition property was investigated using electrochemical methods. The surface investigation of the alloy was achieved using SEM–EDX and XPS. The strength of inhibitor to inhibit corrosion depends on the surfactant concentration, the higher inhibition efficiency was exhibited when the surfactant concentration was higher. The inhibitor appeared as a mixed-type inhibitor. The inhibiting effect of Gemini surfactant showed rapid adsorption on the alloy surface. The experimental results were related to the theoretical findings obtained from the studies based on density function theory (DFT). Graphical Abstract: [Figure not available: see fulltext.]. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.Item Performance of anionic dimeric surfactant on AZ31 Magnesium alloy in neutral medium unveiled through experimental and theoretical investigation(Springer, 2024) Acharya, M.G.; Nityananda Shetty, A.N.The synthesis of a novel eco-friendly anionic Gemini surfactant, pursuing three parameters of green chemistry: economic, environmental factor, and mass reaction efficiency is developed as a corrosion inhibitor for AZ31 Mg alloy. Herein, the corrosion inhibition ability of novel EDTA-based dimeric surfactant on AZ31 Mg alloy in corrosive media with varying concentrations of NaCl and Na2SO4 at temperatures between 30–50 °C were studied. The surfactant’s molecular structure is affirmed by FT-IR, NMR, and LC–MS techniques. Electrochemical techniques and surface morphology were employed to evaluate the corrosion inhibition efficiency. The inhibitor studied exhibited appreciable corrosion inhibition at 30 °C. The surfactant shows physical adsorption as per the data obtained in the Gibbs free energy and enthalpy of adsorption studies. The adsorption of the inhibitor was found to be a film-like layer on the surface of AZ31 Mg alloy and, is confirmed by SEM–EDX and XPS techniques. In addition, theoretical simulations were performed to compare with experimental results. Conclusively, the work provides a deeper understanding of the intricacies involved in the development of a new anionic dimeric surfactant as an effective corrosion inhibitor. © The Author(s) 2024.