Purpose The paper aims to examine the inhibition effect of NiO nanoparticles and the influence of... more Purpose The paper aims to examine the inhibition effect of NiO nanoparticles and the influence of liquid nitrogen immersion on the corrosion behavior of (NiO)x(Bi1.6 Pb0.4)Sr2Ca2Cu3O10-δ and (NiO)x (Bi, Pb 2223), where x = 0.00 and 0.05 Wt.% phase superconductor in 0.1 M Na2SO4 at 30°C. Design/methodology/approach This study was done using open-circuit potential electrochemical impedance spectroscopy, potentiodynamic polarization curves and chronoamperometry measurements. Findings Potentiodynamic polarization technique showed that NiO nanoparticles suppress both the anodic and cathodic parts of the polarization curves of (NiO)x(Bi, Pb)-2223 superconductor in 0.1 M Na2SO4 solution. A significant enhancement in the corrosion resistance of the prepared superconductors is observed on immersing them in liquid nitrogen. This is owing to the fact that immersion in liquid nitrogen increases the volume contraction of the superconductor matrix, causing the shrinkage of the pores and voids pre...
Protection of Metals and Physical Chemistry of Surfaces
The inhibition mechanism of willow (Salix) plant leaf extract on the corrosion of mild steel in 0... more The inhibition mechanism of willow (Salix) plant leaf extract on the corrosion of mild steel in 0.5 M HCl and 0.5 M HNO3 solutions was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques, as well as Fourier transform infrared spectroscopy (FTIR) and Ultra-violet Spectrophotometry (UV). Potentiodynamic polarization curves showed that the willow leaf extract acts as a mixed type inhibitor. The impedance responses in both acidic solutions revealed that the corrosion process occurs under charge transfer control. Three adsorption isotherms including Langmuir, Kinetic-thermodynamic and Florry–Huggins were tested to clarify the mode of inhibition of willow leaf extract. The obtained data showed that willow leaf extract could serve as an effective inhibitor for the corrosion of mild steel in acidic media. However willow was more efficient in 0.5 M HNO3 solutions than in 0.5 HCl solutions.
The inhibitory nature, thermodynamics and adsorptive properties of Phaseolus vulgaris L. extract,... more The inhibitory nature, thermodynamics and adsorptive properties of Phaseolus vulgaris L. extract, known as Fasolia seed extract were evaluated for carbon steel and zinc alloy corrosion in 0.5 M HCl...
The adsorption behavior and the inhibition performance of safranin, an azo dye, for mild steel co... more The adsorption behavior and the inhibition performance of safranin, an azo dye, for mild steel corrosion in 0.5 M hydrochloric acid and citric acid solutions have been carried using potentiodynamic polarization and electrochemical impedance spectroscopy techniques as well quantum chemical calculations. Safranin has shown good inhibition efficiency in both acidic solutions. The impedance responses in both acids indicated that the corrosion process takes place under activation control. Langmuir and kinetic–thermodynamic adsorption isotherms were applied to clarify the mode of safranin inhibition. The obtained results revealed that the corrosion inhibition of mild steel in both acid solutions occurs through a physicochemical adsorption mechanism of safranin. The dissolution mechanism of mild steel in both acids was clarified and discussed.
Solid-state reaction technique was used to prepare superconductor samples with nominal compositio... more Solid-state reaction technique was used to prepare superconductor samples with nominal composition of (SnO2)x(Bi,Pb)-2223 and (NiO)x(Bi,Pb)-2223, where 0.0 ≤ x ≤ 0.2 wt%. The prepared samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The impact of SnO2 and NiO nanoparticles addition on the thermopower of (Bi,Pb)-2223 was measured using a standard differential technique. The Seebeck coefficient values in the presence of NiO nanoparticles were about 5–37.9% higher than those obtained with the addition of SnO2 nanoparticles. Higher values of Seebeck coefficients result in a wide variety of applications of these superconductors such as electronics and thermoelectric devices. The obtained results were analyzed according to the two-band model (Fermi-liquid model) and the two-band model with an extra linear term. The Fermi velocity (υF), Fermi energy, Fermi temperature (TF), Fermi wavenumber (KF), Fermi wavelength (λF) as well as the carrier concentration (N/V) values were calculated and discussed as a function of the nanoparticles content.
Zn0.97Mn0.03O and Zn0.87Mn0.03Fe0.1O nanoparticles have been synthesized using co-precipitation t... more Zn0.97Mn0.03O and Zn0.87Mn0.03Fe0.1O nanoparticles have been synthesized using co-precipitation technique. The obtained nanoparticles were characterized by X-ray diffraction, and transmission electron microscopy. The elemental contents of the prepared nanoparticles were determined using particle-induced X-ray emission. Besides, the oxygen content of these nanoparticles was determined using non-Rutherford backscattering spectroscopy. The electrochemical behaviour of 10 ppm nanoparticles on the corrosion of mild steel in 0.5 M HCl and 0.5 M NaCl solutions containing 1% SDS was studied using potentiodynamic polarization curve measurements and electrochemical impedance spectroscopy techniques. The mechanism of inhibition of the studied nanoparticles was discussed and explained. Iron containing nanoparticles enhanced the corrosion protection of mild steel in 0.5 M HCl due to the ability of Fe2+ to deposit onto metal surface. However, in neutral 0.5 M NaCl medium, both nanoparticles have approximately similar efficiency.
Abstract (NiO)x(Bi1.6 Pb0.4)Sr2Ca2Cu3O10-δ composite, where 0.0 ≤ x ≤ 0.2 wt%., were prepared usi... more Abstract (NiO)x(Bi1.6 Pb0.4)Sr2Ca2Cu3O10-δ composite, where 0.0 ≤ x ≤ 0.2 wt%., were prepared using solid state reaction method. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) as well as transmission electron microscopy (TEM). Vickers microhardness measurements (HV) were carried out at room temperature under different applied loads varying from 0.49 to 9.8 N, and dwell times (40 and 59 s). It was noted that dwell time and Vickers microhardness were inversely proportional. HV values increase as x increases up to 0.1 wt%, and then they decrease with further increases in x. All samples exhibit indentation size effect (ISE) with normal trend, as Vickers microhardness decreases by increasing the applied loads. Also, Vickers microhardness measurements of the prepared samples were done during both loading forces up to 9.8 N and unloading downwards to 0.49 N. It was noted that unloading values of Vickers microhardness are slightly greater than loading values. The elastic/plastic deformation model (EPD) was used to interpret the loading and unloading Vickers microhardness results. It is clearly noted that values of do, the added elastic component the measured plastic indentation semi-diagonal (d),in the unloading results are much higher than those for loading data. The effect of liquid nitrogen immersion for 16 h on Vickers microhardness values was examined. A significant improvement in the Vickers microhardness of (Bi, Pb)-2223 samples immersed in liquid nitrogen was observed. Such behavior is attributed to the fact that nitrogen immersion increases the volume contraction of the superconductor matrix, causing the shrink of the pores and voids present in the samples. Different models were used to analyze the obtained results such as Meyer's law, Hays–Kendall (HK) approach, elastic/plastic deformation (EPD) model, and modified proportional specimen resistance (MPSR) model. The experimental results of Vickers microhardness of both samples without and with liquid nitrogen immersion are well fitted according to the MPSR model.
The excess conductivity and magnetoconductivity of (NiO)x(Bi,Pb)-2223 were analyzed using the Asl... more The excess conductivity and magnetoconductivity of (NiO)x(Bi,Pb)-2223 were analyzed using the Aslamazov and Larkin (AL model) in order to obtain the coherence lengths ξab(0), ξc(0) at 0 K and the anisotropic parameter Γ. Both ξab(0) and ξc(0) values increase with the addition of NiO nanoparticles The anisotropic parameter values Γ in this study are less than those reported due to the polycrystalline nature of these samples.
The corrosion behavior of (SnO2)x(Bi1.6 Pb0.4)Sr2Ca2Cu3O10-δ, (SnO2)x(Bi,Pb)-2223, in 0.5 M NaCl ... more The corrosion behavior of (SnO2)x(Bi1.6 Pb0.4)Sr2Ca2Cu3O10-δ, (SnO2)x(Bi,Pb)-2223, in 0.5 M NaCl solutions at 30 °C was studied using potentiodynamic polarization curves measurements, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques as well as scanning electron microscopy (SEM) and energy dispersive X-ray emission spectroscopy (EDX). The polarization data indicated that SnO2 nanoparticles behave as a cathodic type inhibitor for the corrosion of (Bi-Pb)-2223 phase superconductors in simulating seawater solutions. The corrosion current density of (SnO2)x(Bi,Pb)-2223 in a NaCl solution decreases with the time elapsed from sample preparation. The CV of (SnO2)x(Bi-Pb)-2223 phase superconductors showed features similar to those of ideal capacitive behavior. The results indicated that a pure (Bi,Pb)-2223 phase superconductor is the most suitable choice for electrochemical capacitor applications in simulating seawater solutions. However, EIS measurements a...
The inhibitive mechanism, thermodynamics and adsorptive properties of thiobarbituric acid (TBA) a... more The inhibitive mechanism, thermodynamics and adsorptive properties of thiobarbituric acid (TBA) and thiourea (TU) on the corrosion of mild steel in 0.5 M HNO3 solution have been investigated using potentiodynamic, electrochemical impedance spectroscopy techniques and quantum chemical calculations. Both inhibitors showed good inhibition efficiency in nitric acid solution. TU was the most effective inhibitor and its inhibition efficiency increases with increasing concentration to attain 99% at 6 × 10−3 mol. L−1 at 30 °C. Theoretical fitting of different isotherms, Langmuir, Flory-Huggins, Temkin and the kinetic-thermodynamic models were tested to clarify the nature of inhibitors adsorption on mild steel surface. The obtained experimental data fitted all the applied adsorption isotherms except Langmuir. The thermodynamic activation parameters were determined to provide evidence of the inhibitory effect of TBA and TU. To determine the surface charge at the steel surface in nitric acid solution the potential of zero charge was measured using AC measurements at different potentials. Quantum chemical parameters were calculated and explained. The data clarified that the inhibition of steel in nitric acid by TU or TBA takes place through physico-chemical adsorption mechanism.
Purpose The paper aims to examine the inhibition effect of NiO nanoparticles and the influence of... more Purpose The paper aims to examine the inhibition effect of NiO nanoparticles and the influence of liquid nitrogen immersion on the corrosion behavior of (NiO)x(Bi1.6 Pb0.4)Sr2Ca2Cu3O10-δ and (NiO)x (Bi, Pb 2223), where x = 0.00 and 0.05 Wt.% phase superconductor in 0.1 M Na2SO4 at 30°C. Design/methodology/approach This study was done using open-circuit potential electrochemical impedance spectroscopy, potentiodynamic polarization curves and chronoamperometry measurements. Findings Potentiodynamic polarization technique showed that NiO nanoparticles suppress both the anodic and cathodic parts of the polarization curves of (NiO)x(Bi, Pb)-2223 superconductor in 0.1 M Na2SO4 solution. A significant enhancement in the corrosion resistance of the prepared superconductors is observed on immersing them in liquid nitrogen. This is owing to the fact that immersion in liquid nitrogen increases the volume contraction of the superconductor matrix, causing the shrinkage of the pores and voids pre...
Protection of Metals and Physical Chemistry of Surfaces
The inhibition mechanism of willow (Salix) plant leaf extract on the corrosion of mild steel in 0... more The inhibition mechanism of willow (Salix) plant leaf extract on the corrosion of mild steel in 0.5 M HCl and 0.5 M HNO3 solutions was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques, as well as Fourier transform infrared spectroscopy (FTIR) and Ultra-violet Spectrophotometry (UV). Potentiodynamic polarization curves showed that the willow leaf extract acts as a mixed type inhibitor. The impedance responses in both acidic solutions revealed that the corrosion process occurs under charge transfer control. Three adsorption isotherms including Langmuir, Kinetic-thermodynamic and Florry–Huggins were tested to clarify the mode of inhibition of willow leaf extract. The obtained data showed that willow leaf extract could serve as an effective inhibitor for the corrosion of mild steel in acidic media. However willow was more efficient in 0.5 M HNO3 solutions than in 0.5 HCl solutions.
The inhibitory nature, thermodynamics and adsorptive properties of Phaseolus vulgaris L. extract,... more The inhibitory nature, thermodynamics and adsorptive properties of Phaseolus vulgaris L. extract, known as Fasolia seed extract were evaluated for carbon steel and zinc alloy corrosion in 0.5 M HCl...
The adsorption behavior and the inhibition performance of safranin, an azo dye, for mild steel co... more The adsorption behavior and the inhibition performance of safranin, an azo dye, for mild steel corrosion in 0.5 M hydrochloric acid and citric acid solutions have been carried using potentiodynamic polarization and electrochemical impedance spectroscopy techniques as well quantum chemical calculations. Safranin has shown good inhibition efficiency in both acidic solutions. The impedance responses in both acids indicated that the corrosion process takes place under activation control. Langmuir and kinetic–thermodynamic adsorption isotherms were applied to clarify the mode of safranin inhibition. The obtained results revealed that the corrosion inhibition of mild steel in both acid solutions occurs through a physicochemical adsorption mechanism of safranin. The dissolution mechanism of mild steel in both acids was clarified and discussed.
Solid-state reaction technique was used to prepare superconductor samples with nominal compositio... more Solid-state reaction technique was used to prepare superconductor samples with nominal composition of (SnO2)x(Bi,Pb)-2223 and (NiO)x(Bi,Pb)-2223, where 0.0 ≤ x ≤ 0.2 wt%. The prepared samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The impact of SnO2 and NiO nanoparticles addition on the thermopower of (Bi,Pb)-2223 was measured using a standard differential technique. The Seebeck coefficient values in the presence of NiO nanoparticles were about 5–37.9% higher than those obtained with the addition of SnO2 nanoparticles. Higher values of Seebeck coefficients result in a wide variety of applications of these superconductors such as electronics and thermoelectric devices. The obtained results were analyzed according to the two-band model (Fermi-liquid model) and the two-band model with an extra linear term. The Fermi velocity (υF), Fermi energy, Fermi temperature (TF), Fermi wavenumber (KF), Fermi wavelength (λF) as well as the carrier concentration (N/V) values were calculated and discussed as a function of the nanoparticles content.
Zn0.97Mn0.03O and Zn0.87Mn0.03Fe0.1O nanoparticles have been synthesized using co-precipitation t... more Zn0.97Mn0.03O and Zn0.87Mn0.03Fe0.1O nanoparticles have been synthesized using co-precipitation technique. The obtained nanoparticles were characterized by X-ray diffraction, and transmission electron microscopy. The elemental contents of the prepared nanoparticles were determined using particle-induced X-ray emission. Besides, the oxygen content of these nanoparticles was determined using non-Rutherford backscattering spectroscopy. The electrochemical behaviour of 10 ppm nanoparticles on the corrosion of mild steel in 0.5 M HCl and 0.5 M NaCl solutions containing 1% SDS was studied using potentiodynamic polarization curve measurements and electrochemical impedance spectroscopy techniques. The mechanism of inhibition of the studied nanoparticles was discussed and explained. Iron containing nanoparticles enhanced the corrosion protection of mild steel in 0.5 M HCl due to the ability of Fe2+ to deposit onto metal surface. However, in neutral 0.5 M NaCl medium, both nanoparticles have approximately similar efficiency.
Abstract (NiO)x(Bi1.6 Pb0.4)Sr2Ca2Cu3O10-δ composite, where 0.0 ≤ x ≤ 0.2 wt%., were prepared usi... more Abstract (NiO)x(Bi1.6 Pb0.4)Sr2Ca2Cu3O10-δ composite, where 0.0 ≤ x ≤ 0.2 wt%., were prepared using solid state reaction method. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) as well as transmission electron microscopy (TEM). Vickers microhardness measurements (HV) were carried out at room temperature under different applied loads varying from 0.49 to 9.8 N, and dwell times (40 and 59 s). It was noted that dwell time and Vickers microhardness were inversely proportional. HV values increase as x increases up to 0.1 wt%, and then they decrease with further increases in x. All samples exhibit indentation size effect (ISE) with normal trend, as Vickers microhardness decreases by increasing the applied loads. Also, Vickers microhardness measurements of the prepared samples were done during both loading forces up to 9.8 N and unloading downwards to 0.49 N. It was noted that unloading values of Vickers microhardness are slightly greater than loading values. The elastic/plastic deformation model (EPD) was used to interpret the loading and unloading Vickers microhardness results. It is clearly noted that values of do, the added elastic component the measured plastic indentation semi-diagonal (d),in the unloading results are much higher than those for loading data. The effect of liquid nitrogen immersion for 16 h on Vickers microhardness values was examined. A significant improvement in the Vickers microhardness of (Bi, Pb)-2223 samples immersed in liquid nitrogen was observed. Such behavior is attributed to the fact that nitrogen immersion increases the volume contraction of the superconductor matrix, causing the shrink of the pores and voids present in the samples. Different models were used to analyze the obtained results such as Meyer's law, Hays–Kendall (HK) approach, elastic/plastic deformation (EPD) model, and modified proportional specimen resistance (MPSR) model. The experimental results of Vickers microhardness of both samples without and with liquid nitrogen immersion are well fitted according to the MPSR model.
The excess conductivity and magnetoconductivity of (NiO)x(Bi,Pb)-2223 were analyzed using the Asl... more The excess conductivity and magnetoconductivity of (NiO)x(Bi,Pb)-2223 were analyzed using the Aslamazov and Larkin (AL model) in order to obtain the coherence lengths ξab(0), ξc(0) at 0 K and the anisotropic parameter Γ. Both ξab(0) and ξc(0) values increase with the addition of NiO nanoparticles The anisotropic parameter values Γ in this study are less than those reported due to the polycrystalline nature of these samples.
The corrosion behavior of (SnO2)x(Bi1.6 Pb0.4)Sr2Ca2Cu3O10-δ, (SnO2)x(Bi,Pb)-2223, in 0.5 M NaCl ... more The corrosion behavior of (SnO2)x(Bi1.6 Pb0.4)Sr2Ca2Cu3O10-δ, (SnO2)x(Bi,Pb)-2223, in 0.5 M NaCl solutions at 30 °C was studied using potentiodynamic polarization curves measurements, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques as well as scanning electron microscopy (SEM) and energy dispersive X-ray emission spectroscopy (EDX). The polarization data indicated that SnO2 nanoparticles behave as a cathodic type inhibitor for the corrosion of (Bi-Pb)-2223 phase superconductors in simulating seawater solutions. The corrosion current density of (SnO2)x(Bi,Pb)-2223 in a NaCl solution decreases with the time elapsed from sample preparation. The CV of (SnO2)x(Bi-Pb)-2223 phase superconductors showed features similar to those of ideal capacitive behavior. The results indicated that a pure (Bi,Pb)-2223 phase superconductor is the most suitable choice for electrochemical capacitor applications in simulating seawater solutions. However, EIS measurements a...
The inhibitive mechanism, thermodynamics and adsorptive properties of thiobarbituric acid (TBA) a... more The inhibitive mechanism, thermodynamics and adsorptive properties of thiobarbituric acid (TBA) and thiourea (TU) on the corrosion of mild steel in 0.5 M HNO3 solution have been investigated using potentiodynamic, electrochemical impedance spectroscopy techniques and quantum chemical calculations. Both inhibitors showed good inhibition efficiency in nitric acid solution. TU was the most effective inhibitor and its inhibition efficiency increases with increasing concentration to attain 99% at 6 × 10−3 mol. L−1 at 30 °C. Theoretical fitting of different isotherms, Langmuir, Flory-Huggins, Temkin and the kinetic-thermodynamic models were tested to clarify the nature of inhibitors adsorption on mild steel surface. The obtained experimental data fitted all the applied adsorption isotherms except Langmuir. The thermodynamic activation parameters were determined to provide evidence of the inhibitory effect of TBA and TU. To determine the surface charge at the steel surface in nitric acid solution the potential of zero charge was measured using AC measurements at different potentials. Quantum chemical parameters were calculated and explained. The data clarified that the inhibition of steel in nitric acid by TU or TBA takes place through physico-chemical adsorption mechanism.
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