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Cairo, Egypt

Gobara M.,Egyptian Armed Force | Shamekh M.,Egyptian Armed Force | Akid R.,University of Manchester
Journal of Magnesium and Alloys | Year: 2015

A composite consisting of magnesium matrix reinforced with a network of TiC-Ti2AlC-TiB2 particulates has been fabricated using a practical in-situ reactive infiltration technique. The microstructural and phase composition of the magnesium matrix composite (R-Mg) was investigated using SEM/EDS and XRD. The analyses revealed the complete formation of TiC, Ti2AlC and TiB2 particles in the magnesium matrix. Comparative compression tests of R-Mg and AZ91D alloy showed that the reinforcing particles improve the mechanical properties of Mg alloy. EIS and potentiodynamic polarization results indicated that the reinforcing particles significantly improve the corrosion resistance of the reinforced alloy in 3.5% NaCl solution. © 2015 National Engineering Research Center for Magnesium Alloys of China, Chongqing University.

Gobara M.,Egyptian Armed Force | Baraka A.,Egyptian Armed Force | Zaghloul B.,Egyptian Armed Force
Research on Chemical Intermediates | Year: 2015

Calotropis Gigantiea latex (CGL) was used for adsorptive inhibition of corrosion of carbon steel in 0.5 M H2SO4 solution. Inhibition was studied through potentiodynamic polarization and electrochemical impedance spectroscopy. Adsorption isotherm data was recorded at different temperature settings to reveal characteristics of adsorptive inhibition and to determine energetic features of adsorption. Results indicated that CGL is a suitable green inhibitor for the corrosion of carbon steel in solutions of H2SO4 , with efficiency reaching up to 97 %. The inhibition efficiency of CGL was found to increase with increasing inhibitor concentration, but to decrease with increasing temperature. The adsorption of CGL on the carbon steel surface was found to be spontaneous and exothermic, and it was fitted with the Langmuir isotherm and found to obey the physisorption mechanism. Scanning electron microscope was employed to examine changes in the metal surface in the presence and absence of the inhibitor. © Springer Science+Business Media Dordrecht 2015.

Gobara M.,Egyptian Armed Force | Baraka A.,Egyptian Armed Force | Zaghloul B.,Egyptian Armed Force
Research on Chemical Intermediates | Year: 2015

Inhibitive effect of collagen on the acid corrosion of mild steel in 0.5 M H2SO4 solution was studied by electrochemical impedance spectroscopy and electrochemical frequency modulation. Collagen effectively inhibited the corrosion of mild steel with efficiency ranges from 88.9 to 96.5 % for collagen concentrations from 20 to 80 ppm. Adsorption isotherm study was performed using weight loss measurements where Langmuir and El-Awady models were applied on data to investigate the mode of adsorption. Corrosion inhibition was also tested at different temperatures to measure the thermodynamic parameters; ΔG°, ΔH°, ΔS° and E a. Inhibition is suggested to occur due to adsorption phenomenon and data obey the El-Awady model. Thermodynamic study reveals that adsorption is endothermic-physical process driven by entropic factors. © 2014 Springer Science+Business Media Dordrecht.

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