Iranian Journal of Materials Science and Engineering

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Abstract: In this paper solid state reduction of high carbon ferrochromium-chromite composite pellets in the temperature range of 900-1350°C was investigated. A two stage reduction mechanism is proposed. The first stage is likely to be controlled by the chemical reaction with activation energy of 127.2kJ/mol. In the second stage, solid state diffusion of carbon through the reaction product layer is suggested to be rate controlling. The activation energy of this stage was calculated to be 93.1kJ/mol. The reduction process was found to be favored by high temperatures as well as high vacuum. The results also show that pre-milling of initial mixture has a negative effect on the reduction degree.

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In this research an ultra-fine grained composite structure consisting of an intermetallic matrix together with dispersed nano-sized Al2O3 obtained via mechanical activation of TiO2 and Al in a high energy ball mill and sintering of consolidated samples. Phase composition and morphology of the milled and sintered samples were evaluated by XRD and SEM techniques Thermal behavior of the powder sample milled for 8 hours was evaluated by DTA technique. DTA results showed that, the reaction happens in two steps. The first step is the aluminothermic reduction of TiO2 with Al. XRD observations reveals that minor amount of Ti3Al phase formed during reduction reaction together with TiAl and Al2O3 major phases. This intermetallic phase disappeared when sintering temperature was increased to 850 ºC. The second step in DTA is related to a reaction between residual Al in the system (partly dissolved in TiAl lattice) and the Ti3Al phase produced earlier at lower temperatures. SEM micrographs reveal that by completion of the reduction reaction more homogeneous and finer microstructure is observable in sintered samples.

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Accumulative roll-bonding process (ARB) is an important severe plastic deformation technique for production of the ultrafine grained, nanostructured and nanocomposite materials in the form of plates and sheets. In the present work, this process used for manufacturing Al/SiO 2 nanocomposites by using Aluminum 1050 alloy sheets and nano sized SiO 2 particles, at ambient temperature. After 8 cycles of ARB process, the tribological properties and wear resistance of produced nanocomposites were investigated. The wear tests by abrasion were performed in a pinon-disc tribometer. Results show that by increasing ARB cycles and the amount of nano powders, the friction coefficient of produced nanocomposites decreases.

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The purpose of this research is to achieve the optimal parameters for producing forged aluminium alloy 7075 aircraft door bracket by using finite element modelling (FEM) with commercial DEFORM-3D V6.1 and physical simulations with plasticine and Plexiglas dies. Also, forging speed has been examined as the main factor for controlling to produce a part without any defects. The results of Physical Simulation showed that the flow pattern has good agreement with the results of FEM that based on the use of hydraulic presses with initial billet and dies temperatures 410 and 400 ° C, respectively, and different forging speeds 5, 10 and 15 mm/sec. Distribution of effective strain rate, effective strain, effective stress, temperature , forging force and dies­ wear showed improvement the results in forging speed of 5 mm/sec. Processing map of Aluminium alloy 7075 also checked out at constant strain 0.5, indicated that the specified area of the forged part is located in a safe area. Forging force in optimized forging speed 5 mm/sec showed that the forging process using a 1000-ton press can be done easily

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In this work, the facile synthesis and identification of hexylmethylimidazolium bis(trifluoromethyl­sulfonyl)­amide ([HMIM]­TFSA) and hexylmethylimidazolium triethyltrifluorophosphate ([HMIM]FAP) ionic liquids (ILs), as multifunctional and multipurpose gear oil additives, is introduced. The tribological tests indicated that both ([HMIM]TFSA) and ([HMIM]FAP) ILs demonstrate antiwear/extreme pressure properties (AW/EP) to the gear oils by preventing wear and scar of the lubricated system at low and high temperatures. [HMIM]TFSA provided superior performance in comparison to [HMIM]FAP. Because of the presence of heteroaromatic imidazole moiety in the ILs structure, the prepared ILs also imparted anticorrosion, antioxidant, and anti-rust properties to the lubricant. All these observations confirmed that the ILs are single component multifunctional and multipurpose oil additives. In addition, due to avoiding the use of toxic and harmful elements in the preparation of ILs make the fabricated oils potential candidates for green lubricants.

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Copper oxide thin layers were elaborated using the sol-gel dip-coating. The thickness effect on morphological, structural, optical and electrical properties was studied. Copper chloride dihydrate was used as precursor and dissolved into methanol. The scanning electron microscopy analysis results showed that there is continuity in formation of the clusters and the nuclei with the increase of number of the dips. X-ray diffractogram showed that all the films are polycrystalline cupric oxide CuO phase with monoclinic structure with grain size in the range of 30.72 - 26.58 nm. The obtained films are clear blackin appearance, which are confirmed by the optical transmittance spectra. The optical band gap energies of the deposited films vary from 3.80 to 3.70 eV. The electrical conductivity of the films decreases from 1.90.10^-2 to 7.39.10^-3 (Ω.cm)^-1

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In this work, blast furnace slag (BFS) was used as an adsorbent material for the removal of Pb(II) ions in solution in batch mode. The physico-chemical analyzes used indicated that the BFS is essentially composed of silica, lime, and alumina. Its specific surface area corresponds to 275.8m²/g and its PZC is around 3.8.
The adsorption study indicated that the maximum amount of Pb(II) adsorbed under optimum conditions (agitation speed (V_ag): 150rpm; pH: 5.4; particle size (Øs): 300µm, T: 20°C) is 34.26mg/g after 50 minutes of agitation, and adsorption yield is best for feeble initial concentrations. The most appropriate isothermal model was that of Langmuir, and the adsorption speed was better characterized by the pseudo-second order kinetic model. The adsorption mechanism revealed that internal diffusion is not the only mechanism that controls the adsorption process; there is also external diffusion, which contributes enormously in the transfer of Pb(II) from solution to adsorbent. Thermodynamic study indicated that the Pb(II) adsorption on the blast furnace slag (BFS) was spontaneous, exothermic, and that the adsorbed Pb(II) is more ordered at the surface of the adsorbent. Finally, we estimate that BFS is a superb adsorbent for water containing Pb(II).
 

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In this study, we thoroughly examine β-Bi₂O₃ thin films as potential photocatalysts. We produced these films using an environmentally friendly Sol Gel method that is also cost-effective. Our research focuses on how different precursor concentrations, ranging from 0.1 M to 0.4 M, affect the photocatalytic performance of these films. We conducted a comprehensive set of tests to analyze various aspects of the films, including their structure, morphology, topography, optical properties, wettability, and photocatalytic capabilities. These tests provided us with a well-rounded understanding of the films' characteristics. To assess their photocatalytic efficiency, we used Methylene Blue (MB) as a contaminant and found that the films, particularly those with a 0.1 M concentration, achieved an impressive 99.9% degradation of MB within four hours. The 0.1 M film had a crystalline size of 39.7 nm, an indirect band gap of 2.99 eV, and a contact angle of 51.37°. Our findings suggest that β-Bi₂O₃ films, especially the 0.1 M variant, have promising potential for treating effluents from complex industrial dye processes. This research marks a significant step in utilizing sustainable materials to address pollution and environmental remediation challenges.

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In this research work, Cadmium Sulphide thin film deposited on to glass substrate in a non-aqueous medium at 80 °C. The various physical preparative parameters and the deposition conditions, such as the deposition time and temperature, concentrations of the chemical species, pH, speed of mechanical stirring, etc., were optimized to yield good quality films. The as-prepared sample is tightly adherent to the substrate's support, less smooth, diffusely reflecting and was analyzed for composition. The synthesized film is characterized using X- ray diffraction (XRD), electrical and optical properties. It appears that the composites are rich in Cd. The grown CdS thin film had an orange-red color. A band gap of CdS thin film is 2.41 eV.  The average crystallite size of the CdS film was 21.50 nm. The resistivity of the CdS thin film is about 5.212 x 10⁵ W cm.
 

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The paper investigates the solar photodegradation of Methylene Blue dye using copper oxide (CuO) thin films synthesized by the Successive Ionic Layer Adsorption and Reaction (SILAR) method. The structural, morphological, and optical characteristics of the CuO thin films have been investigated by employing a variety of methods, such as Fourier transform Infrared (FTIR) spectroscopy, UV-Vis spectroscopy, Scanning electron microscopy (SEM), and X-ray diffraction (XRD). The outcomes showed that CuO thin films with excellent surface shape and a highly crystalline nature had been successfully deposited. Methylene Blue was subjected to solar radiation during its photodegradation process, and the outcomes showed a significant decrease in the dye's concentration over time. To maximize the photo degradation process, the effects of other experimental factors were also assessed, such as the starting concentration of MB, the quantity of CuO thin film, number of SILAR cycles and the pH of the solution. Good photocatalytic activity is demonstrated by CuO thin films produced using the SILAR approach in the solar photodegradation of methylene blue. The development of affordable and ecologically friendly wastewater treatment technology that can use sun energy to break down persistent organic contaminants is affected by these findings.
 

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Nowadays metal oxide nanoparticles and transition metal dichalcogenides play a vital role in various areas like optical sensors, solar cells, energy storage devices, gas sensors and biomedical applications. In the current research work, we synthesized ZrSe₂ nanoparticles by hydrothermal method. The ZrSe₂ nanoparticles were synthesis using precursors such as ZrOCl₂.8H₂O and Na₂SeO₃.5H₂O in the addition of surfactant cetyl trimethyl ammonia bromide CTAB and reductant hydrazine hydrate, respectively. By using synthesized ZrSe₂ nanopowder thick films were developed on a glass substrate
using the screen printing method. The structural properties of ZrSe₂ powder were studied by X-ray diffraction (XRD). The X-ray diffraction analysis revealed that the hexagonal crystal structure and crystalline size were found to be 55.75 nm. The thick films of ZrSe₂ were characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray analysis (EDAX). The surface morphological analysis of ZrSe₂ nanostructured thick film shows hierarchical nanoparticles. The energy band gap of synthesized powder was calculated using a Tauc plot from UV-visible spectroscopy. The gas-sensing properties of ZrSe₂ thick films were studied. The developed ZrSe₂ thick films show maximum sensitivity and selectivity towards the ammonia NH₃ gas at an operating temperature of 120 °C and the gas concentration was 500 ppm. The developed thick films show fast response and recovery time.Nowadays metal oxide nanoparticles and transition metal dichalcogenides play a vital role in various areas like optical sensors, solar cells, energy storage devices, gas sensors and biomedical applications. In the current research work, we synthesized ZrSe₂ nanoparticles by hydrothermal method. The ZrSe₂ nanoparticles were synthesis using precursors such as ZrOCl₂.8H₂O and Na₂SeO₃.5H₂O in the addition of surfactant cetyl trimethyl ammonia bromide CTAB and reductant hydrazine hydrate, respectively. By using synthesized ZrSe₂ nanopowder thick films were developed on a glass substrate
using the screen printing method. The structural properties of ZrSe₂ powder were studied by X-ray diffraction (XRD). The X-ray diffraction analysis revealed that the hexagonal crystal structure and crystalline size were found to be 55.75 nm. The thick films of ZrSe₂ were characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray analysis (EDAX). The surface morphological analysis of ZrSe₂ nanostructured thick film shows hierarchical nanoparticles. The energy band gap of synthesized powder was calculated using a Tauc plot from UV-visible spectroscopy. The gas-sensing properties of ZrSe₂ thick films were studied. The developed ZrSe₂ thick films show maximum sensitivity and selectivity towards the ammonia NH₃ gas at an operating temperature of 120 °C and the gas concentration was 500 ppm. The developed thick films show fast response and recovery time.