Ashraf Moustafa Abdel-Gaber

The target of this research was to identify the occurrence of the longitudinal facial crack (LFC) defect during the casting of a low-carbon, low-manganese flat steel product. Despite the severity of this defect which may be minor, it turned out unacceptable in the final product due to the remarkable production losses associated with reproducing the product. Electrochemical testing was executed on samples of the LFC defect, which were compared to a control sample. Additionally, Selected LFC samples were also analyzed using scanning electron microscopy and energy-dispersive X-ray spectroscopy at various process parameters such as carbon equivalent, isostatic flow control, non-metallic inclusion, mold flux to determine the root cause of the LFC defect. The findings of this investigation revealed that optimizing specific process parameters in both the thin slab caster and the melt shop effectively controlled the appearance of LFC defects. By manipulating these parameters, it was possible to mitigate the occurrence of LFC defects and prevent the associated economic losses, which result from having to reproduce the product. The likelihood of LFC defects can be drastically reduced by identifying and solving the underlying root causes of the defect, such as adjusting carbon equivalent, isostatic flow control material, managing non-metallic inclusions, and improving mold flux. These results underline how crucial it is to properly optimize the process variables in order to guarantee the manufacture of premium low-carbon, low-manganese flat steel products.

The corrosion behaviour of (Bi, Pb)-2223 samples compacted at 0.3–1.9 GPa in 0.5 M of HCl, NaCl, and NaOH solutions at 30 °C was investigated using potentiodynamic polarization curves measurements and electrochemical impedance spectroscopy (EIS) technique as well as scanning electron microscopy (SEM) and energy dispersive X-ray emission spectroscopy (EDX). Polarization results showed that the increase in compaction decreases both cathodic hydrogen evolution or oxygen reduction and anodic (BiPb)-2223 superconductor dissolution in 0.5 M HCl, and 0.5 M NaOH. On the other hand, compaction mainly affects the anodic part of the polarization curves of (Bi, Pb)-2223 in 0.5 M NaCl solution. EIS measurements revealed that the highest protection of the superconductors was achieved in 0.5 M NaCl, while the lowest degree of protection was observed in 0.5 M HCl. SEM images show a random plate-like morphology fitted with the marker of (Bi, Pb)-2223 material. The compacted sample at 1.9 GPa indicates deformation of the grains and the formation of a micro-crack. The corrosion mechanism of the superconductor at different pH values was also discussed.

The corrosion behaviour of (Bi, Pb)-2223 samples compacted at 0.3–1.9 GPa in 0.5 M of HCl, NaCl, and NaOH solutions at 30°C was investigated using potentiodynamic polarization curves measurements and electrochemical impedance spectroscopy (EIS) technique as well as scanning electron microscopy (SEM) and energy dispersive X-ray emission spectroscopy (EDX). Polarization results showed that the increase in compaction decreases both cathodic hydrogen evolution or oxygen reduction and anodic (BiPb)-2223 superconductor dissolution in 0.5 M HCl, and 0.5 M NaOH. On the other hand, compaction mainly affects the anodic part of the polarization curves of (Bi, Pb)-2223 in 0.5 M NaCl solution. EIS measurements revealed that the highest protection of the superconductors was achieved in 0.5 M NaCl, while the lowest degree of protection was observed in 0.5 M HCl. SEM images show a random plate-like morphology fitted with the marker of (Bi, Pb)-2223 material. The compacted sample at 1.9 GPa indicates deformation of the grains and the formation of a micro-crack. The corrosion mechanism of the superconductor at different pH values was also discussed.

Superhydrophobic films were successfully designed for a copper substrate using potentiostatic deposition of Ni and Ni-graphene composite followed by treatment with stearic acid (SA). A scanning electron microscope was used to examine the surface morphology of the prepared superhydrophobic films, and the results revealed that both Ni-SA and Ni-graphene-SA films have micro-nano structures. FTIR measurements revealed that the copper substrates had been coated with Ni-SA and Ni-graphene-SA films. The Ni-graphene-SA film has the highest chemical stability and mechanical abrasion resistance. Potentiodynamic polarization and electrochemical impedance spectroscopy results indicated that the formulated superhydrophobic films on the copper substrate have high corrosion resistance in 0.5 M NaCl.

Zinc oxide (ZnO) nanoparticles (NPs) were synthesized using the coprecipitation method. The resulting NPs were characterized by X‐ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The surface morphology of the coatings has been characterized by scanning electron microscopy (SEM). SEM images show a uniform and homogeneous distribution of ZnO‐NPs in polyurethane (PU) coatings while aggregates appear in epoxy coatings. Using tensile stress–strain test, the effect of the addition of ZnO‐NPs on the mechanical properties of PU and epoxy coatings was examined. The addition of ZnO‐NPs has enhanced the Young's modulus and the tensile strength of PU and epoxy coatings. Through the open‐circuit potential and electrochemical impedance spectroscopy measurements, the anticorrosive properties of PU‐ or epoxy‐coated mild steel panels containing ZnO‐NPs have been investigated in 0.5 M NaCl solution. Nyquist impedance plots for PU and epoxy coatings in PU‐ or epoxy‐coated mild steel panels containing ZnO‐NPs were tested in the absence and presence of ZnO‐NPs have different responses. It has been shown that the dispersion of ZnO‐NPs significantly improves the anticorrosive performance of PU coatings. A PU coating containing 700 mg/kg ZnO‐NPs is recommended to achieve better mechanical properties and corrosion resistance.

The inhibition mechanism of willow (Salix) plant leaf extract on the corrosion of mild steel in 0.5 M HCl and 0.5 M HNO3solutions was investigated using potentiodynamic polarization and...