M.j Kadhim, Fatima Allawi, M. A. Mahdi, Sami Najah Abaas,
Volume 19, Issue 3 (September 2022)
Abstract
Zinc Oxide (ZnO) nanorods and titanium dioxide (TiO2) nanostructures thin films were prepared onto glass substrates by the chemical bath deposition (CBD) method. The ZnO was structured as nanorods (NRs) while TiO2 was formed as nanoflowers plate as confirmed by Field-Emission Scanning Electron Microscope (FESEM) images. The ZnO/Fe3O4 and TiO2/Fe3O4 nanostructures thin films were prepared via drop-casting Fe3O4 NPs onto the grown ZnO and TiO2 nanostructures thin films. The diameter of Fe3O4 NPs was deposited onto ZnO NRs thin films and TiO2 nanostructures thin films was ranged from 8nm to 59nm with dominated range between 10nm to 30 nm. The crystalline structure of prepared samples was investigated through X-ray diffraction (XRD) method. However, the particles size of Fe3O4 was estimated by XRD as well as FESEM images was around 22 nm. The photocatalytic activity of the as-prepared ZnO/Fe3O4 and TiO2/Fe3O4 nanostructures thin films was investigated against methylene blue (MB) dye at room temperature with a pH value of 10 under different exposure time by visible light. The photodegradation rate of MB dye by ZnO/Fe3O4 and TiO2/Fe3O4 nanostructures thin films was higher than that obtained by ZnO and TiO2 nanostructures thin films. The best photodegradation rate of MB dye was 100% after exposure time of 180 min was obtained by ZnO/Fe3O4 nanostructures thin film whereas it was 82% for TiO2/Fe3O4 nanostructures thin films after exposure time of 240 min.
Asaad Kadhim Eqal, Haidar Akram Hussein,
Volume 23, Issue 3 (September 2026)
Abstract
The influence of different heat treatment parameters, namely solutionizing and artificial
aging conditions, on the microstructure, mechanical hardness, and corrosion resistance of Al-
12Si-Cu alloy are systematically explored in this work. Solution treatment was performed at
two temperatures (500°C and 530°C) and two durations (0.5 and 3 hours), and artificial aging
was made at two temperatures (180°C and 310°C) over two durations (2 and 5 hours).
Optical microscopy also showed interesting microstructural changes with fine grain
refinement and enhanced spheroidization of the coarse eutectic Si phase and a more uniform
distribution of primary intermetallic grains. These structural adjustments were identified as
direct determinants of properties of the material. Maximum microhardness (155 HV) was
achieved at the temperatures of 500°C/3 h solutionizing and 180°C for 5 h aging (S3), which
was ascribed to successful solid solution strengthening and fine precipitation hardening. In
contrast, the lowest hardness (54 HV) was obtained at the values 530°C/3 h + 310°C/5 h (S8),
showing the harmful impact of over-aging at higher temperatures. Analysis of
electrochemical corrosion detected a significant correlation between the corrosion resistance
and treated microstructure, where conditions favoring microstructural refinement resulted in a
decrease in corrosion current density. A Design of Experiments (DOE) method by way of the
Taguchi L8 orthogonal array was used to find out how each parameter contributed relative to
the other variable. The analysis revealed that, whilst the aging temperature was the most
influential factor to the microhardness, the solution time was the controlling factor on the
surface roughness. The results demonstrate a robust determination of the main processing
windows which are known to be crucial to enhance particular properties and verify the
tremendous feasibility of temperature control in heat treatment process optimization in
engineering the necessary trade-off between mechanical strength and corrosion performance
in Al-12Si-Cu alloys.
