Browsing by Author "Geetha, G.M."

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    Adsorption and inhibitor action of 4-(N,N-dimethylamino) benzaldehyde thiosemicarbazone on 6061 Al/SiC composite and its base alloy in sulfuric acid medium
    (2011) Geetha, G.M.; Nayak, J.; Nityananda Shetty, A.N.
    The inhibitive action of 4-(N,N-dimethylamino)benzaldehyde thiosemicarbazone (DMABT) on the corrosion behavior of 6061 Al -15 vol. pct. SiC(p) composite and its base alloy was studied at different temperatures in sulfuric acid medium containing varying concentrations of it, using Tafel extrapolation technique and AC impedance spectroscopy (EIS). Results showed that DMABT was an effective inhibitor, showing inhibition efficiency of 70% in 0.5 M sulfuric acid. The adsorption of DMABT on both the composite and base alloy was found to be through physisorption obeying Langmuir adsorption isotherm. The thermodynamic parameters such as free energy of adsorption and activation parameters were calculated. © Taylor & Francis Group, LLC.
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    Corrosion behaviour of 6061 Al - 15vol. Pct. SiC composite and its base alloy in a mixture of 1:1 Hydrochloric and sulphuric acid medium
    (2009) Geetha, G.M.; Nayak, J.; Nityananda Shetty, A.N.
    Silicon carbide particulate - reinforced aluminum (SiCp-Al) composites possess a unique combination of high specific strength, high elastic modulus, good wear resistance and good thermal stability than the corresponding non-reinforced matrix alloy systems. These composites are potential structural material for aerospace and automotive applications. The corrosion characteristics of 6061 Al/SiCp composite and the base alloy were experimentally assessed. The corrosion test was carried out at different temperatures in 1:1 mixture of hydrochloric acid and sulphuric acid at a concentration range of 0.01 to 1N for each of the acid, as corrosion media using Tafel extrapolation technique and Electrochemical impedance spectroscopy (EIS). The results obtained from Tafel extrapolation technique and Electrochemical impedance spectroscopy were in good agreement. The results showed an increase in the corrosion rate with increases in temperature as well as the increase in the concentration of the corrosion media. The thermodynamic parameters like energy of activation were calculated using Arrhenius theory equation and, enthalpy of activation and entropy of activation were calculated using transition state theory equation. © 2009 by ESG.
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    Corrosion inhibition of 6061 Al-15 vol. pct. SiC(p) composite and its base alloy in a mixture of sulphuric acid and hydrochloric acid by 4-(N,N-dimethyl amino) benzaldehyde thiosemicarbazone
    (2011) Geetha, G.M.; Nayak, J.; Nityananda Shetty, A.N.
    The corrosion inhibition characteristics of 4-(N,N-dimethylamino) benzaldehyde thiosemicarbazone (DMABT) on the corrosion behavior of 6061 Al-15 vol. pct. SiC(p) composite and its base alloy were studied at different temperatures in acid mixture medium containing varying concentrations of hydrochloric acid and sulphuric acid using Tafel extrapolation technique and ac impedance spectroscopy (EIS). The effect of inhibitor concentration, temperature and concentration of the acid mixture media on the inhibitor action was investigated. It was found that inhibition efficiencies increase with the increase in inhibitor concentration, but decrease with the increase in temperature and with the increase in concentration of the acid media. Thermodynamic parameters for dissolution process were determined. The adsorption of DMABT on both the composite and base alloy was found to be through physisorption obeying Freundlich adsorption isotherm. © 2010 Elsevier B.V. All rights reserved.