Faculty Publications
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Item The inhibiting effect of N - cyclohexyl - N?- phcnyl thiourea (CPTU) and N-naphthyl-N?- phenyl thiourea (NPTU) on the corrosion of mild steel in aqueous solution of 0.1 N H2SO4 have been demonstrated using potentiodynamic polarization technique. The polarization data have shown that these compounds act as efficient anodic inhibitors for mild steel. Adsorption of these compounds on the mild steel surface was found to obey Temkin's adsorption isotherm. Good inhibition efficiency (IE) was evidenced in both the compounds and it was found to vary with concentration of the inhibitors. The kinetic parameters of adsorption obtained reveal spontaneous adsorption and a strong interaction of the compounds on the mild steel surface. © 2006 SAEST.(Inhibition of mild steel corrosion in sulphuric acid solution) Divakara Shetty, S.; Shetty, P.; Sudhaker Nayak, H.V.2006Item The inhibition efficiency of Glycyl Glycine (GG) on the corrosion behaviour of Al-SiC(p) composite in 0.01, 0.1 and 1.0 N HCl solution has been investigated in the temperature range 30°-50°C using polarization techniques. The results indicate that GG acts as an anodic inhibitor and is chemisorbed following Temkin's model. The inhibitor efficiency increases with increase in inhibitor concentration and also with increase in temperature for a given inhibitor concentration. © 2006 SAEST.(Glycyl glycine as corrosion inhibitor for aluminium silicon carbide composite in hydrochloric acid) Rao, S.A.; Padmalatha; Nayak, J.; Nityananda Shetty, A.N.2006Item 3-Methyl-4-amino-5-mercapto-1,2,4-triazole as corrosion inhibitor for 6061 Al alloy in 0.5 M sodium hydroxide solution(Springer New York LLC barbara.b.bertram@gsk.com, 2011) Kumari, P.D.R.; Nayak, J.; Nityananda Shetty, A.N.3-Methyl-4-amino-5-mercapto-1,2,4-triazole (MAMT) was synthesized, and its inhibition action on the corrosion of 6061 Al alloy in 0.5 M sodium hydroxide was investigated by means of potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The effect of inhibitor concentration, temperature, and concentration of the corrosion medium on the inhibitor action was investigated. The surface morphology of the metal surface was investigated by scanning electron microscopy (SEM). The inhibition efficiency increased with the increase in the concentration of the inhibitor, but decreased with the increase in temperature. Both thermodynamic and kinetic parameters were calculated and discussed. The adsorption of MAMT on the base alloy was found to be through physisorption, obeying Langmuir's adsorption isotherm. The results obtained from both the techniques were in good agreement with each other. © 2011 ACA and OCCA.Item 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.Item 3,4-Dimethoxybenzaldehydethiosemicarbazone as corrosion inhibitor for aged 18 Ni 250 grade maraging steel in 0.5 M sulfuric acid(2011) Poornima, T.; Nayak, J.; Nityananda Shetty, A.N.The corrosion inhibition of the aged 18 Ni 250 grade maraging steel in 0.5 M sulfuric acid by 3,4-dimethoxybenzaldehydethiosemicarbazone(DMBTSC) has been investigated by potentiodynamic polarization and electrochemical impedance spectroscopy(EIS) techniques. The inhibition efficiency increased with the increase in inhibitor concentration and decreased with the increase in temperature. Polarization curves indicated mixed type inhibition behavior affecting both cathodic and anodic corrosion currents. The thermodynamic parameters of corrosion and adsorption processes were evaluated. The adsorption of DMBTSC on the aged maraging steel surface was found to obey the Langmuir adsorption isotherm model, and the calculated Gibb's free energy values confirm the spontaneous adsorption. The results obtained by the two techniques were in good agreement. © 2010 Springer Science+Business Media B.V.Item Effect of 4-(N,N-diethylamino)benzaldehyde thiosemicarbazone on the corrosion of aged 18 Ni 250 grade maraging steel in phosphoric acid solution(2011) Poornima, T.; Nayak, J.; Nityananda Shetty, A.N.4-(N,N-diethylamino)benzaldehyde thiosemicarbazone (DEABT) was studied for its corrosion inhibition property on the corrosion of aged 18 Ni 250 grade maraging steel in 0.67M phosphoric acid at 30-50°C by potentiodynamic polarization, EIS and weight loss techniques. Inhibition efficiency of DEABT was found to increase with the increase in DEABT concentration and decrease with the increase in temperature. The activation energy Ea and other thermodynamic parameters (?Gads0, ?Hads0, ?Sads0) have been evaluated and discussed. The adsorption of DEABT on aged maraging steel surface obeys the Langmuir adsorption isotherm model and the inhibitor showed mixed type inhibition behavior. © 2011 Elsevier Ltd.Item The corrosion inhibition of maraging steel under weld aged condition by 1(2E)-1-(4-Aminophenyl)-3-(2-Thienyl)prop-2-en-1-one in 1.5 M hydrochloric acid medium(Springer New York LLC barbara.b.bertram@gsk.com, 2012) Sanatkumar, B.S.; Nayak, J.; Nityananda Shetty, A.N.The influence of 1(2E)-1-(4-Aminophenyl)- 3-(2-Thienyl)prop-2-en-1-one (ATPI) on the corrosion behavior of weld aged maraging steel in 1.5 M hydrochloric acid was studied by potentiodynamic polarization method and AC impedance (EIS) technique at different temperatures. The results showed that the inhibition efficiency of ATPI increased with the increase in the concentration of inhibitor and decreased with the increase in temperature. ATPI acts as a mixed type inhibitor without affecting the mechanism of the hydrogen evolution reaction or iron dissolution. The adsorption of ATPI on a weld aged maraging steel surface obeys the Langmuir adsorption isotherm equation. Both activation and thermodynamic parameters were calculated and discussed. ATPI inhibits the corrosion through both physisorption and chemisorption on the alloy surface. The surface morphology of the weld aged maraging steel specimens in the presence and the absence of the inhibitors was studied by the respective SEM images. © ACA and OCCA 2011.Item Influence of 2-(4-chlorophenyl)-2-oxoethyl benzoate on the hydrogen evolution and corrosion inhibition of 18 Ni 250 grade weld aged maraging steel in 1.0 M sulfuric acid medium(2012) Sanatkumar, B.S.; Nayak, J.; Nityananda Shetty, A.N.Electrochemical corrosion behavior and hydrogen evolution reaction of weld aged maraging steel have been investigated, in 1.0 M sulfuric acid solution containing different concentrations of 2-(4-chlorophenyl)-2-oxoethyl benzoate (CPOB). The data obtained from polarization technique showed that the corrosion current density (i corr) and the hydrogen evolution rate decrease, indicating a decrease in the corrosion rate of weld aged maraging steel as well as an increase in the inhibition efficiency (?%) with the increase in inhibitor concentration. Changes in impedance parameters were indicative of adsorption of CPOB on the metal surface, leading to the formation of protective film. Both activation (E a) and thermodynamic parameters (?G ads 0, ?H ads 0 and ?S ads 0) were calculated and discussed. The adsorption of CPOB on the weld aged maraging steel surface obeyed the Langmuir adsorption isotherm model. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) study confirmed the formation of an adsorbed protective film on the metal surface. © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Item Protective performance of furfuryl alcohol on 13Cr L80 steel against corrosion in hydrochloric acid solution(2014) Puthalath, P.; Surendranathan, A.O.; Murthy, Ch.S.N.The search for efficient inhibitors to mitigate the corrosion of oil-well steels requires more experimental investigations of the performance of ecofriendly nontoxic organic inhibitors. With this objective, the inhibitive action of a selected inhibitor, furfuryl alcohol (FAL), on the corrosion resistance of 13Cr L80 steel in 15% HCl solution was investigated using weight-loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. The inhibition efficiency of furfuryl alcohol was found to increase almost linearly with concentration and reached about 96% at 90 mM but decreased with temperature. The adsorption of the inhibitor on 13Cr L80 steel in the acidic solution was found to accord with the Langmuir isotherm. Thermodynamic and activation parameters were also evaluated. Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA) were carried out to establish the inhibitive properties of FAL. The results from these tests confirmed that FAL is a potential inhibitor for 13Cr L80 steel in HCl acid medium. © 2013 American Chemical Society.Item Inhibition effect of adsorption layer of 1-phenyl-4-(4-nitrophenyl) thiosemicarbazide on the corrosion of 18 Ni 250-grade welded maraging steel in 1.0 M hydrochloric acid medium(Kluwer Academic Publishers, 2015) Kumar, P.; Nityananda Shetty, A.N.The thiosemicarbazide derivative, 1-phenyl-4-(4-nitrophenyl)thiosemicarbazide (PNPT), was synthesized and its inhibiting action on the corrosion of welded maraging steel in 1.0 M hydrochloric acid was investigated by electrochemical methods of potentiodynamic (Tafel) polarization and electrochemical impedance spectroscopy. The inhibitor, PNPT, acted essentially as a mixed-type inhibitor with predominant cathodic action. The inhibition efficiency increased with the increase in inhibitor concentration. An inhibition efficiency of about 86 % was exhibited at 30 °C, which decreased with the increase in the temperature. The adsorption of the inhibitor layer formed was through predominant physical adsorption process. © 2014 Springer Science+Business Media Dordrecht.