8-hydroxy-7-phenylazo-quinoline-5-sulfonicacid derivatives as corrosion inhibitors for copper in nitric acid solutions

Author/s: Prof. Dr. A. S. Fouda, K. El-Shiekh, S. Abd El-Maksoud and Prof. M. A. Diab
Posted on Tuesday, May 24, 2016

Prof. Dr. A. S. Fouda
Fig. 9: Molecular orbital plots of investigated compounds
Fig. 1: Weight loss-time curves for the dissolution of copper in the absence and presence of different concentrations of compound (1) at 300 0C
Fig. 8: EFM spectra for copper in of 1 M HNO3 in the absence and presence of 21x10-6 M compound (1)
Tab. 9: Calculated quantum chemical parameters for investigated compounds
Fig. 3: Log k (corrosion rate) - l/T curves for copper dissolution in 1M HNO3 in absence and presence of different concentrations of compound (1)

Corrosion Inhibition of copper in nitric acid by 8-hydroxy-7-phenylazo-quinoline-5-sulfonicacid derivatives have been studied using weight loss and electrochemical measurements. The results showed that these derivatives act as moderate corrosion inhibitor for copper at all concentrations of these derivatives. All results indicate that the inhibition efficiency increases with increasing inhibitor concentrations. Polarization curves revealed that these derivatives are mixed type inhibitors. The adsorption of these derivatives on the surface of the copper specimens obeys Temkin adsorption isotherm. Some thermodynamic and kinetic parameters for the corrosion process were calculated and discussed. Some quantum chemical parameters for these derivatives calculated by the density function theory (DFT) semi-empirical method to provide further insight into the mechanism of inhibition of the corrosion process.

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Optimization of Ni-P bath for coatings of maximum hardness and thickness by Taguchi’s statistical approach

Author/s: Prof. Dr. A. Chitharanjan Hegde and Liju Elias
Posted on Monday, April 25, 2016

Fig. 1: Hull Cell used for optimization of bath: a) Plan view and b) top view
Fig. 2: Graphical representation showing the variation of micro-hardness at different conditions of bath variables
Fig. 3: Graphical representation showing the variation of thickness of the coating at different conditions of bath variables
Tab. 1: Composition and operating parameters of basic bath for electrodeposition of bright Ni-P alloy
Tab. 2: Factors and the levels selected for electrodeposition of Ni-P alloy coating
Tab. 3: Experimental layout (L9) employed for optimizing the process parameters for electrodeposition of Ni-P alloy on mild steel at 303K
Liju Elias Research Scholar, Electrochemistry Research Laboratory, Department of Chemistry, National Institute of Technology Karnataka, Surathkal Srinivasnagar-575025, India
Prof. Dr. A. Chitharanjan Hegde Professor and Former Head, Department of Chemistry, National Institute of Technology Karnataka, Surathkal Srinivasnagar-575025, India

Incredible claims of electroplating in materials synthesis lies in tailoring its property by proper modulation of the bath composition and operating parameters, such as current density (c.d.), pH and temperature. Electroplating of metals/ alloys is one of the most complex process because of the unusually large number of critical elementary phenomena involved during deposition. Due to lack of quantitative guiding principles to develop a coating of desired property, it is very difficult and time consuming to optimize the bath composition. Even though Hull Cell method is an established method to optimize a bath, in terms of its constituents and operating parameters its application is limited to know only the effect of c.d. on deposit patterns; and is incapable for predicting the desired properties of the coating, like hardness, reflectivity, thickness etc. In this direction, this paper describes Taguchi’s statistical method for optimization of deposition conditions of Ni-P alloy, using Minitab 16, Statistical software, by reducing the number of experiments to a practical level. In the present study, bath variables, i.e., [glycerol], c.d. and pH of the bath are taken as chosen parameters and micro-hardness and thickness of the coatings as parameters for characteristic performance. Experimental conditions were optimized to maximize the coating properties. Taguchi’s method demonstrated that the basic Ni-P bath, having [glycerol] = 20 mL L^-1, c.d.= 4.0 A dm^-2and pH = 8.0 as ideal for developing coatings of highest micro-hardness and thickness. Experimental data revealed that both [glycerol] and c.d. have close dependency on thickness and micro-hardness of coating, compared to pH of the solution. The experimental steps followed for applying Taguchi’s method, for tailoring the deposit characters are discussed with Tables and Figures.

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Cephalexin as Efficient Corrosion Inhibitor for Mild Steel in Acidic Media Chemical, Electrochemical and Thermodynamic Studies

Author/s: Prof. Dr. A. S. Fouda, E. M. Mabrouk and M. Y. El-Banawy
Posted on Thursday, March 31, 2016

Fig. 13: The optimized molecular structures, HOMO, LUMO
Prof. Dr. A. S. Fouda
Tab. 9: The calculated quantum chemical parameters for Cephalexin compound using PM3.
Tab. 8: Electrochemical kinetic parameters obtained by EFM technique for mild steel in 0.5 M H2SO4 solutions with different concentration of investigated drug
Fig. 12: Intermodulation spectrum for mild steel in 0.5 M H2SO4 solutions with 600 ppm of investigated compound at 25 ºC
Fig. 11: Intermodulation spectrum for mild steel in 0.5 M H2SO4 solutions without investigated compound at 25 ºC.
Fig. 1: Molecular structure of Cephalexin Molecular formula: C16H17N3O4S, Molecular weight: 347.39
Fig. 9: The bode plot for mild steel in 0.5 M H2SO4 solution in the absence and presence of different concentrations of the investigated drug

The corrosion inhibition of mild steel in 0.5 M H₂SO₄solution by pharmaceutical antibacterial drug named Cephalexin has been investigated by using weight loss, potentiodynamic polarization, electrochemical frequency modulation technique (EFM) and electrochemical impedance spectroscopy (EIS) measurements. The polarization data showed that this drug is mixed-type inhibitor. The percentage inhibition efficiency was found to increase with increasing the concentration of the drug and with decreasing temperature. The Langmuir`s isotherm was found to provide an accurate description of adsorption behavior of this drug. Some thermodynamic parameters were computed and discussed. The correlations between advanced quantum chemical concepts and inhibition efficiency was found and discussed. The data obtained from different methods are in good agreement.

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Corrosion protection of 6061 Al-15 Vol. Pct. SiC_(p) composite using a biopolymer- An electrochemical approach

Author/s: Prof. Dr. R. Padmalatha and B. P. Charitha
Posted on Tuesday, February 16, 2016

Fig. 6: Bode magnitude plots for the corrosion of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl at 35 °C in the presence of various concentration of inhibitor
Fig. 5: Bode phase plots for the corrosion of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl at 35 °C in the presence of various concentration of inhibitors
Fig. 4a: Equivalent circuit used to simulate for the obtained impedance values
Fig. 4b: Impedance data obtained for 6061 Al-15 vol. pct. SiC(P) composite corrosion in 0.05M HCl at 35 °C
Fig. 3: Impedance plot for corrosion control of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl at 35 °C
Fig. 2: Potentiodynamic polarization curves for the corrosion of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl containing various [starch] at 35 °C
Fig. 1: FTIR spectrum of starch
Fig. 14(a): XRD spectrum for corroded 6061 Al-15 vol. pct. SiC(P) composite
Fig. 14(b): XRD spectrum for 6061 Al-15 vol. pct. SiC(P) composite immersed in inhibited solution
Fig. 13a
Fig. 13b
Fig. 13c
Fig. 12a
Fig. 12b
Fig. 12c /// Fig. 12: SEM image of 6061 Al-15 vol. pct. SiC(P) composite material of a) freshly polished surface, b) immersed in 0.05 M HCl medium, c) immersed in 0.05 M HCl medium + 800ppm starch at 30℃
Fig. 11(b): Structure of amylopectin
Fig. 11(a): Structure of amylose
Fig. 10: ΔG0 ads vs T plot
Fig. 9: Langmuir adsorption isotherm for the adsorption of starch on 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl at different temperature
Fig. 8: Plots of ln(CR/T) vs 1/T for the corrosion of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl containing different concentration of inhibitors
Fig.7: Plots of ln(CR) verses 1/T for corrosion inhibition of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl containing different concentration of inhibitors
Tab. 2: Results of Potentiodynamic polarization studies for corrosion of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl containing various [starch]
Tab. 3: Impedance values obtained for the corrosion 6061 Al-15 vol. pct. SiC(P) composite in 0.05 M HCl in the absence and presence of various concentrations of starch
Tab. 4: Activation parameters for the corrosion of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl containing different concentrations of inhibitor
Tab. 5: Thermodynamic parameters for the corrosion of 6061 Al-15 vol. pct. SiC(P) composite in 0.05M HCl
Tab. 6: EDX data obtained for 6061 Al-15 vol. pct. SiC(P) composite surface analysis
Tab. 7: AFM data obtained for 6061 Al-15 vol. pct. SiC(P) composite surface analysis

The influence of biopolymer starch as corrosion inhibitor on 6061 Al-15 vol. pct. SiC_(p)composite in 0.05M hydrochloric acid was studied by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) technique. The surface morphology was studied using SEM, EDX, AFM and XRD techniques. The results showed that the inhibition efficiency of starch increased with increasing inhibitor concentrations and also with increase in temperatures. Starch acted as a mixed inhibitor and underwent chemical adsorption following Langmuir adsorption isotherm.

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Malonic Acid as Corrosion Inhibitor for Carbon Steel in 1 M Hydrochloric Acid Solutions

Author/s: Prof. Dr. A. S. Fouda and Salah Habouba
Posted on Thursday, October 8, 2015

Fig. 10: SEM micrographs of carbon steel surface (a) before of immersion in 1 M HCl, (b) after 3 h of immersion in 1 M HCl and (c) after 3 h of immersion in 1 M HCl + 300 ppm of malonic acid at 25°C
Tab. 1: Data of mass loss measurements for carbon steel in 1M HCl solution in the absence and presence of various concentrations of malonic acid 25°C
Tab. 2: Potentiodynamic data of carbon steel in 1 M HCl and in the presence of various concentrations of malonic acid at 250C
Tab. 3: EIS data of carbon steel in 1 M HCl and in the presence of various concentrations of malonic acid at 25°C
Tab. 4: Electrochemical kinetic parameters obtained by EFM technique for carbon steel in the absence and presence of various concentrations of malonic acid in 1 M HCl at 25ºC
Tab. 5: Activation parameters for dissolution of carbon steel the absence and presence of various concentrations of malonic acid in 1 M HCl
Tab.: 6 Surface composition (wt %) of carbon steel before and after immersion in 1 M HCl without and with 300 ppm of malonic acid at 25°C

The protection effect of malonic acid on carbon steel corrosion was studied in aerated stagnant 1M HCl solutions at 25⁰C. Measurements were conducted under different experimental conditions using weight loss, Tafel polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. malonic acid was found to be good inhibitor of carbon steel corrosion in1 M HCl. The adsorption of this inhibitor is found to obey the Langmuir adsorption isotherm. The calculated activation energies proposed that the inhibitor molecules being physically adsorbed onto the metal surface. Polarization data revealed that this compound behave as mixed type inhibitor.

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JEPT – Journal for Electrochemistry and Plating Technology

Edited by: DGO-Fachausschuss Forschung – Hilden / Germany

Category Archives: General

8-hydroxy-7-phenylazo-quinoline-5-sulfonicacid derivatives as corrosion inhibitors for copper in nitric acid solutions

Optimization of Ni-P bath for coatings of maximum hardness and thickness by Taguchi’s statistical approach

Cephalexin as Efficient Corrosion Inhibitor for Mild Steel in Acidic Media Chemical, Electrochemical and Thermodynamic Studies

Corrosion protection of 6061 Al-15 Vol. Pct. SiC_(p) composite using a biopolymer- An electrochemical approach

Malonic Acid as Corrosion Inhibitor for Carbon Steel in 1 M Hydrochloric Acid Solutions