A continuing challenge in materials design is the achievement of greater operational efficiency t... more A continuing challenge in materials design is the achievement of greater operational efficiency through improvements in performance criterion, particularly, high strength and service lifetime characteristics. In this study, we report on the effect of heat treatment (annealing) on the stress corrosion cracking (SCC) behavior of α-brass (71Cu−28Zn) in aqueous electrolytes containing some aggressive anions (Cl−, ClO3−, NO2−, and SO42−). The annealed specimens suffered from SCC in all tested electrolytes under the anodic polarization conditions while they were susceptible to SCC only in NaNO2 and Na2SO4 solutions under the open circuit condition. The susceptibility toward SCC was found to decrease considerably in NaCl, KClO3, and Na2SO4 solutions and very slightly in NaNO2 solutions upon annealing the specimens.
One of the major challenges in material design is the achievement of reasonable operational effic... more One of the major challenges in material design is the achievement of reasonable operational efficiency through understanding the factors affecting the material’s performance particularly strength and service lifetime characteristics. In this work, the electrochemical behavior of 72Cu–28Zn α-brass alloy in Na2MoO4-containing electrolytes was investigated using potentiodynamic polarization and electrochemical frequency modulation techniques complemented with scanning electron microscopy. Also, stress corrosion cracking behavior of the alloy under both open-circuit potential and anodic applied potentials, using the slow strain rate technique, was evaluated. The results drawn from the different techniques are comparable.
The inhibiting effect of Roselle extract (Krd) on carbon steel in 0.5 MHCl
solution was investiga... more The inhibiting effect of Roselle extract (Krd) on carbon steel in 0.5 MHCl solution was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) methods. It was found that Krd extract acts as a good inhibitor for carbon steel corrosion in the acid solution. The results showed that Krd extract simultaneously retarded the hydrogen evolution on the cathode and the metal dissolution on the anode, which indicated that this inhibitor is an excellent mixed-type (cathodic/anodic) inhibitor. The dissolution rate decreases with increasing Krd extract concentration and increases with increasing the temperature. The adsorption of Krd extract on the active cathodic sites was found to follow the Langmuir adsorption isotherm. The maximum inhibition approached 91.0 % in the presence of 500 ppm Krd using the EFM technique. The formation of a protective film on the carbon steel surface in the presence of Krd was shown and confirmed by SEM results. There are good agreements between EIS, EFM, the potentiodynamic polarization data, and SEM/EDX results.
Electrochemical techniques were used to investigate the effect of cysteine (cys) on the dissoluti... more Electrochemical techniques were used to investigate the effect of cysteine (cys) on the dissolution behavior of Cu10Ni alloy in sulfide-polluted salt water through the analysis of the alloy electrochemical behavior including Tafel polarization and electrochemical frequency modulation (EFM) along with scanning electron microscopy (SEM) and energy dispersive X-ray diffraction (EDX). The results showed that cys acts as a mixed type inhibitor. The dissolution rate decreases with increasing cys concentration and increases with increasing the temperature. An adherent layer of inhibitor molecules on the alloy surface is proposed to account for their inhibitive action. The adsorption of cys on the active cathodic sites was found to follow the Langmuir adsorption isotherm from which the thermodynamic parameters of adsorption and corrosion processes were determined and discussed. A synergistic effect was observed between cys and potassium iodide (KI). EFM data are in good agreement with SEM and EDX results.
The stress corrosion cracking (SCC) behaviour of α-Aluminum bronze (Cu7Al) has been investigated ... more The stress corrosion cracking (SCC) behaviour of α-Aluminum bronze (Cu7Al) has been investigated in nitrite solution under open circuit and at different anodic potentials and compared to α-brass using the constant slow strain rate technique. The electrochemical behavior was also studied using Tafel and electrochemical frequency modulation (EFM) techniques. While α-brass was quite susceptible to SCC in relatively concentrated NaNO2 and highly anodic potentials, α-Al bronze was found to be resistant to SCC. The resistance of α-Al bronze to SCC was attributed to the presence of Al2O3 on its surface. Although the time to failure and stress ratio remained virtually constant for α-Al bronze, they decreased sharply with increasing the anodic potential in the case of α-brass. The mode of failure was predominantly ductile for α-Al bronze under various conditions. Previous findings for the change of the mode of failure from intergranular at open circuit potential to transgranular cracking under anodic potentials were confirmed. The electrochemical corrosion parameters obtained from potentiodynamic polarization and electrochemical frequency modulation (EFM) are in good agreement.
A continuing challenge in materials design is the achievement of greater operational efficiency t... more A continuing challenge in materials design is the achievement of greater operational efficiency through improvements in performance criterion, particularly high strength and service life-time characteristics in this study we report on the evaluation of di-sodium hydrogen phosphate (DSHP) as an inhibitor for the stress corrosion cracking (SCC) of 67Cu-33Zn alloy in 0.1 M NaNO2 and 3.5% NaCl aqueous electrolytes under both open-circuit potential (OCP) and relatively high anodic potential (300 mV(NHE)) using the slow strain rate (SSR) technique. DSHP has been found to inhibit SCC of the tested brass alloy which is in parallel with the results obtained from electrochemical measurements. The inhibitive effect of DSHP can be attributed to the formation of a three dimensional film of zinc phosphate on the alloy surface which in turn inhibits dezincification and subsequently the SCC of the 67/33 brass alloy. On the other hand, the addition of 0.1 M DSHP was found to change the failure mode from brittle transgranular cracking to ductile failure. The results of both electrochemical and SCC measurements were combined together to investigate the inhibitive mechanism of DSHP
Corrosion is a natural and inevitable problem that is still a challenge in materials design, with... more Corrosion is a natural and inevitable problem that is still a challenge in materials design, with regard to achieving greater operational efficiency. In this study, the electrochemical and stress corrosion cracking (SCC) behavior of Cu10Ni alloy in a 3.5% NaCl solution in the presence of different concentrations of sulfide ions were studied. The presence of sulfide ions has been shown to increase the susceptibility of the material to SCC at different strain rates. The addition of glycine (gly) to the test electrolyte increased the time to failure by changing the mode of failure from brittle transgranular cracking to ductile failure. Therefore, gly can be considered as a potential environmentally friendly corrosion inhibitor. The electrochemical measurements showed that gly acts as a mixed corrosion inhibitor. The synergistic effect of potassium iodide (KI) and gly is also investigated. Electrochemical frequency modulation (EFM) and potentiodynamic polarization data are in good agreement with the SCC results.
A continuing challenge in materials design is the achievement of high operational efficiency thro... more A continuing challenge in materials design is the achievement of high operational efficiency through improvements in performance criterion, particularly its service life-time characteristics. Benzotriazole (BTAH) has now been in use for many years for the protection of copper and copper alloys against various forms of corrosion. In this review, the chemistry of BTAH and theories regarding its mode of action are summarized. Also, a survey of the reported work in both clean and polluted environments is documented. More interestingly, the adverse effect of BTAH on the corrosion of Cu and Cu alloys in sulfide polluted environments is introduced.
A continuing challenge in materials design is the achievement of greater operational efficiency t... more A continuing challenge in materials design is the achievement of greater operational efficiency through improvements in performance criterion, particularly, high strength and service lifetime characteristics. In this study, we report on the effect of heat treatment (annealing) on the stress corrosion cracking (SCC) behavior of α-brass (71Cu−28Zn) in aqueous electrolytes containing some aggressive anions (Cl−, ClO3−, NO2−, and SO42−). The annealed specimens suffered from SCC in all tested electrolytes under the anodic polarization conditions while they were susceptible to SCC only in NaNO2 and Na2SO4 solutions under the open circuit condition. The susceptibility toward SCC was found to decrease considerably in NaCl, KClO3, and Na2SO4 solutions and very slightly in NaNO2 solutions upon annealing the specimens.
One of the major challenges in material design is the achievement of reasonable operational effic... more One of the major challenges in material design is the achievement of reasonable operational efficiency through understanding the factors affecting the material’s performance particularly strength and service lifetime characteristics. In this work, the electrochemical behavior of 72Cu–28Zn α-brass alloy in Na2MoO4-containing electrolytes was investigated using potentiodynamic polarization and electrochemical frequency modulation techniques complemented with scanning electron microscopy. Also, stress corrosion cracking behavior of the alloy under both open-circuit potential and anodic applied potentials, using the slow strain rate technique, was evaluated. The results drawn from the different techniques are comparable.
The inhibiting effect of Roselle extract (Krd) on carbon steel in 0.5 MHCl
solution was investiga... more The inhibiting effect of Roselle extract (Krd) on carbon steel in 0.5 MHCl solution was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) methods. It was found that Krd extract acts as a good inhibitor for carbon steel corrosion in the acid solution. The results showed that Krd extract simultaneously retarded the hydrogen evolution on the cathode and the metal dissolution on the anode, which indicated that this inhibitor is an excellent mixed-type (cathodic/anodic) inhibitor. The dissolution rate decreases with increasing Krd extract concentration and increases with increasing the temperature. The adsorption of Krd extract on the active cathodic sites was found to follow the Langmuir adsorption isotherm. The maximum inhibition approached 91.0 % in the presence of 500 ppm Krd using the EFM technique. The formation of a protective film on the carbon steel surface in the presence of Krd was shown and confirmed by SEM results. There are good agreements between EIS, EFM, the potentiodynamic polarization data, and SEM/EDX results.
Electrochemical techniques were used to investigate the effect of cysteine (cys) on the dissoluti... more Electrochemical techniques were used to investigate the effect of cysteine (cys) on the dissolution behavior of Cu10Ni alloy in sulfide-polluted salt water through the analysis of the alloy electrochemical behavior including Tafel polarization and electrochemical frequency modulation (EFM) along with scanning electron microscopy (SEM) and energy dispersive X-ray diffraction (EDX). The results showed that cys acts as a mixed type inhibitor. The dissolution rate decreases with increasing cys concentration and increases with increasing the temperature. An adherent layer of inhibitor molecules on the alloy surface is proposed to account for their inhibitive action. The adsorption of cys on the active cathodic sites was found to follow the Langmuir adsorption isotherm from which the thermodynamic parameters of adsorption and corrosion processes were determined and discussed. A synergistic effect was observed between cys and potassium iodide (KI). EFM data are in good agreement with SEM and EDX results.
The stress corrosion cracking (SCC) behaviour of α-Aluminum bronze (Cu7Al) has been investigated ... more The stress corrosion cracking (SCC) behaviour of α-Aluminum bronze (Cu7Al) has been investigated in nitrite solution under open circuit and at different anodic potentials and compared to α-brass using the constant slow strain rate technique. The electrochemical behavior was also studied using Tafel and electrochemical frequency modulation (EFM) techniques. While α-brass was quite susceptible to SCC in relatively concentrated NaNO2 and highly anodic potentials, α-Al bronze was found to be resistant to SCC. The resistance of α-Al bronze to SCC was attributed to the presence of Al2O3 on its surface. Although the time to failure and stress ratio remained virtually constant for α-Al bronze, they decreased sharply with increasing the anodic potential in the case of α-brass. The mode of failure was predominantly ductile for α-Al bronze under various conditions. Previous findings for the change of the mode of failure from intergranular at open circuit potential to transgranular cracking under anodic potentials were confirmed. The electrochemical corrosion parameters obtained from potentiodynamic polarization and electrochemical frequency modulation (EFM) are in good agreement.
A continuing challenge in materials design is the achievement of greater operational efficiency t... more A continuing challenge in materials design is the achievement of greater operational efficiency through improvements in performance criterion, particularly high strength and service life-time characteristics in this study we report on the evaluation of di-sodium hydrogen phosphate (DSHP) as an inhibitor for the stress corrosion cracking (SCC) of 67Cu-33Zn alloy in 0.1 M NaNO2 and 3.5% NaCl aqueous electrolytes under both open-circuit potential (OCP) and relatively high anodic potential (300 mV(NHE)) using the slow strain rate (SSR) technique. DSHP has been found to inhibit SCC of the tested brass alloy which is in parallel with the results obtained from electrochemical measurements. The inhibitive effect of DSHP can be attributed to the formation of a three dimensional film of zinc phosphate on the alloy surface which in turn inhibits dezincification and subsequently the SCC of the 67/33 brass alloy. On the other hand, the addition of 0.1 M DSHP was found to change the failure mode from brittle transgranular cracking to ductile failure. The results of both electrochemical and SCC measurements were combined together to investigate the inhibitive mechanism of DSHP
Corrosion is a natural and inevitable problem that is still a challenge in materials design, with... more Corrosion is a natural and inevitable problem that is still a challenge in materials design, with regard to achieving greater operational efficiency. In this study, the electrochemical and stress corrosion cracking (SCC) behavior of Cu10Ni alloy in a 3.5% NaCl solution in the presence of different concentrations of sulfide ions were studied. The presence of sulfide ions has been shown to increase the susceptibility of the material to SCC at different strain rates. The addition of glycine (gly) to the test electrolyte increased the time to failure by changing the mode of failure from brittle transgranular cracking to ductile failure. Therefore, gly can be considered as a potential environmentally friendly corrosion inhibitor. The electrochemical measurements showed that gly acts as a mixed corrosion inhibitor. The synergistic effect of potassium iodide (KI) and gly is also investigated. Electrochemical frequency modulation (EFM) and potentiodynamic polarization data are in good agreement with the SCC results.
A continuing challenge in materials design is the achievement of high operational efficiency thro... more A continuing challenge in materials design is the achievement of high operational efficiency through improvements in performance criterion, particularly its service life-time characteristics. Benzotriazole (BTAH) has now been in use for many years for the protection of copper and copper alloys against various forms of corrosion. In this review, the chemistry of BTAH and theories regarding its mode of action are summarized. Also, a survey of the reported work in both clean and polluted environments is documented. More interestingly, the adverse effect of BTAH on the corrosion of Cu and Cu alloys in sulfide polluted environments is introduced.
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Papers by A. Nazeer
solution was investigated by potentiodynamic polarization, electrochemical impedance
spectroscopy (EIS), electrochemical frequency modulation (EFM), scanning
electron microscopy (SEM), and energy dispersive X-ray (EDX) methods. It was
found that Krd extract acts as a good inhibitor for carbon steel corrosion in the acid
solution. The results showed that Krd extract simultaneously retarded the hydrogen
evolution on the cathode and the metal dissolution on the anode, which indicated that
this inhibitor is an excellent mixed-type (cathodic/anodic) inhibitor. The dissolution
rate decreases with increasing Krd extract concentration and increases with increasing
the temperature. The adsorption of Krd extract on the active cathodic sites was found to
follow the Langmuir adsorption isotherm. The maximum inhibition approached
91.0 % in the presence of 500 ppm Krd using the EFM technique. The formation of a
protective film on the carbon steel surface in the presence of Krd was shown
and confirmed by SEM results. There are good agreements between EIS, EFM, the
potentiodynamic polarization data, and SEM/EDX results.
solution was investigated by potentiodynamic polarization, electrochemical impedance
spectroscopy (EIS), electrochemical frequency modulation (EFM), scanning
electron microscopy (SEM), and energy dispersive X-ray (EDX) methods. It was
found that Krd extract acts as a good inhibitor for carbon steel corrosion in the acid
solution. The results showed that Krd extract simultaneously retarded the hydrogen
evolution on the cathode and the metal dissolution on the anode, which indicated that
this inhibitor is an excellent mixed-type (cathodic/anodic) inhibitor. The dissolution
rate decreases with increasing Krd extract concentration and increases with increasing
the temperature. The adsorption of Krd extract on the active cathodic sites was found to
follow the Langmuir adsorption isotherm. The maximum inhibition approached
91.0 % in the presence of 500 ppm Krd using the EFM technique. The formation of a
protective film on the carbon steel surface in the presence of Krd was shown
and confirmed by SEM results. There are good agreements between EIS, EFM, the
potentiodynamic polarization data, and SEM/EDX results.