Iranian Journal of Materials Science and Engineering

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Copper oxide (CuO) nanostructure particles were prepared using KOH/NaOH catalyst by low cost precipitation method and characterized by powder X-ray diffraction (PXRD), scanning electron microscope (SEM) and energy dispersive X-ray spectra (EDX) analysis. The photocatalytic dye degradation study of pure CuO nanostructure particles are analysed against two azo dyes (Direct black 38 (Black-E) and Congo red) under ultraviolet (UV) and solar irradiation. The release of major active species (*OH) in the photocatalytic degradation by as prepared CuO nanostructure particles were investigated by photoluminescence (PL) spectra with two different excitation wavelength (325and 355nm). The band gap of CuO nanostructure particles was calculated from diffuse reflectance spectra. The photocatalytic effect of CuO nanostructure particles is confirmed from the UV – Vis and photoluminescence spectra and also, further confirmed from the kinetic studies under UV and solar radiations. The photocatalytic degradation results revealed that 16.35% and 7.5% of black E and Congo red dye was degraded under UV, while it was 47.2% and 17.6% under solar light. The influence of pH on the photodegradation and change in the reaction temperature under solar irradiation were also analysed

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Porous nanostructured SnO₂ with a sheet-like morphology was synthesized through a simple green substrate-free gelatin-assisted calcination process using Tin tetracholoride pentahydrate as the SnO₂ precursor and porcine gelatin as the template. Crystalline phase, morphology, microstructure, and optical characteristics of the as-prepared material were also investigated at different calcination temperatures using X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), UV-visible absorption, and Photoluminescence spectroscopy (PL), respectively. XRD patterns of all the samples revealed the presence of a tetragonal crystalline structure with no other crystalline phases. Moreover, the synthesized hierarchical sheets assembled with nanoparticles displayed a large surface area and porous nanostructure. The calculated optical band gap energy varied from 2.62 to 2.87 eV depending on the calcination temperature. Finally, photoluminescence spectra indicated that the nanostructured SnO₂ could exhibit an intensive UV-violet luminescence emission at 396 nm, with shoulders at 374, violet emission peaks at 405 and 414 nm, blue-green emission peak at 486 nm, green emission peak at 534 nm and orange emission peak at 628 nm.

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Hot Workability and Processing Map of High Gd Content Mg-Gd-Zn-Zr-Nd Alloy Hot deformation behavior of homogenized Mg-4Sn binary alloy was studied using compression tests at the temperature range of 300-500  and strain rates of 0.001-1s^-1. The material showed typical single peak flow behavior followed by a steady state flow as a plateau, which is more evident at the high value of Zener-Hollomon parameter. Constitutive analysis showed that in spite of the original Johnson-Cook (J-C), conventional strain compensated Arrhenius model based on Sellars-McTegart model has a reasonable agreement with the experimental data. Moreover, the well-known hyperbolic sine function fits the experimental data for predicting of the peak stress with a fair degree of accuracy.

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     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.  
 

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The present study used a hydrothermal technique to synthesize undoped and Mn2+ doped CdS/Zn3(PO4)2 semiconducting nanocomposite materials. Powder X-ray diffraction, scanning electron microscopy, UV-Vis diffuse reflectance spectrometer, Fourier transform-Infrared Spectroscopy-FT-IR, and photoluminescence techniques were employed to study structural, optical, and luminescence properties of produced nanocomposites. The hexagonal structure of CdS and the monoclinic structure of Zn3(PO4)2 are both reflected in the powder X-ray diffraction spectra. When Mn2+ ions are present in the host lattice, a lattice distortion occurs, causing a phase change from the phase of γ-Zn3(PO4)2 to the β-phase of Zn3(PO4)2, without affecting the hexagonal phase of CdS. The average crystallite size of produced nanocomposites was 22-25 nm, and also calculated the lattice strain and dislocation density to better understand internal deformation of the samples. The FT-IR spectra were used to investigate the molecular vibrations and functional groups in the samples. The surface morphology of the nanocomposites is hexagonal spheres on rectangular shaped nano-flakes, and the interatomic distance between the hexagonal spheres is decreased as the doping concentration increases, forming a rod-like structure on the flakes. EDAX results confirm the presence of various relevant elements in the prepared samples. The quantum confinement of produced samples reduces as the Mn2+ doping concentration in the host lattice increases. The photoluminescence results demonstrate shallow trapped states due to the transition: d-d (4T1 → 6A1) of the tetrahedrally coordinated Mn2+ states and the impact of Mn2+ ions exhibiting several peaks in the UV-Visible region (365-634 nm) generating RGB (Red, Green, Blue) luminescence. Color coordinates and CCT values were calculated using the CIE diagram, and color correlated temperatures in the range of 2513–7307 K were discovered, which might be used in solid state lighting applications.

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We report a simple and practical approach for the easy production of superhydrophobic coatings based on TiO₂-SiO₂@PDMS. In this study, we used tetraethylorthosilicate (TEOS) and titanium tetraisopropoxide (TTIP) as a precursor for the sol-gel synthesis of SiO₂ and TiO₂, respectively. Afterward, the surface of nanoparticles was modified by 1,1,1,3,3,3-hexamethyldisilazane (HMDS) before being combined with polydimethylsiloxane (PDMS). The hydrophobic property of coatings was evaluated by static contact angle measurements. The phase composition and structural evolution of the coatings were examined by X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analysis. It was shown that changing the weight ratio of the solution composition of the coating can affect the hydrophobicity of the surface. The best sample has shown a superhydrophobic property with a 153˚ contact angle which contained (75%TiO₂-25%SiO₂) and PDMS at a weight ratio of 1:1. Moreover, the results showed that the superhydrophobic coating retains its hydrophobic properties up to a temperature of 450 ˚C, and at higher temperatures, it converts to a super hydrophilic with a water contact angle close to 0 ˚. The SiO₂-TiO₂@PDMS coating degrades methylene blue by about 55% and was shown to be capable of photocatalytically decomposing organic pollutants.

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In this study, poly(3-hexylthiophene) (P3HT) and fullerene Indene-C₆₀ multi-adducts (ICxA) were blended to create a formulation as a solution and thin films, which were prepared under ambient conditions. The optical properties of various compositional ratios were studied using UV-Visible absorbance and photoluminescence (Pl) measurements. The energy gaps of the prepared thin films and solutions were determined, and their values increased with increasing fullerene ratio because of the isolation of P3HT chains from their neighbors. Intensity ratio (I_C=C/I_C-C) with a small value in addition to a low value of full width at high maximum (FWHM) of Raman spectra are associated with increased conformation and high aggregation of composition. Furthermore, according to X-ray diffraction  (XRD) results the 1:0.8 and 1:0.6 ratios have the largest crystallite sizes in comparison to the other ratios. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) levels for blends by electrochemical measurements were determined, which are sandwiched between those of the pure materials. In ambient conditions, binary organic photovoltaic cells (OPVs) at different ratios of the photoactive layer were evaluated. The device with a ratio of 1:0.6 had the best performance, with power conversion efficiency (PCE) of 1.21 %, open circuit voltage (V_OC) of 0.53 V, short circuit current density (J_SC) of  5.71 mA.cm^-2, and fill factor (FF) of 39.5 % at a small V_loss of 1.39 V.

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In the present study, bulk refined-structured Al 5083 alloy with high mechanical properties was successfully fabricated by hot consolidation process of nanostructured melt- spun flakes. The influence of cooling rate and pressing conditions on the microstructure and mechanical properties of the alloy were investigated using X-ray diffractometer (XRD), optical microscopy (OM), field emission scanning electron microscopy (FE-SEM), microhardness, and compression tests. Rapid solidification combined with the hot consolidation at T=753 K (480 °C) and P= 800 MPa for 20 min produced a bulk sample with the desirable bonding, good microhardness (184.2±12.4 HV), and high strength (273±8 MPa) combined with 7 pct. fracture strain. These amounts are 78.6±5.1 HV, 148 ±9 MPa and about 5 pct. for the as-cast sample. Microstructural refinement during the controlled consolidation of nanostructure rapidly- solidified flakes contributes to such high mechanical properties of the bulk sample.

 

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In this study, CoFe₂O₄  (CoF) and ZnFe₂O₄ (ZnF) photocatalysts were successfully prepared by a facile and simple chemical precipitation method for degradation of methylene blue (MB) and methyl orange (MO) dyes under direct sunlight irradiation. The obtained ferrites were then characterized through XRD, TEM, EDS, UV-vis, and SEM. XRD and TEM results exhibited cubic nanostructures with sizes ranging from 9 to 16 nm and 11 to 18 nm for ZnF and CoF, respectively. SEM images showed homogenous, porous flat surfaces. EDS spectra confirmed the successful synthesis of ZnF and CoF nanostructures with high purity. UV-vis spectra results of MB and MO dyes showed maximum sunlight absorbance in the absence of ZnF and CoF, while a regular decrease in the sunlight absorbance was observed in the presence of ZnF and CoF within 15-60 min. The UV-vis results also showed that ZnF had higher photocatalytic activity than CoF. The experimental findings showed that the highest % degradation was 92.89% and 96.89% for MO and MB dyes, respectively, over ZnF compared to CoF photocatalyst (87.55% and 88.41% for MO and MB, respectively). These findings confirm that porous ZnF and CoF nanostructures are critical in promoting the degradation of dyes under sunlight instead of UV-vis light lamps that consume/require electrical energy.

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CuS nanoparticles (NPs) with dimensions in the nanometer range were synthesized using a wet chemical approach. The comprehensive characterization of these NPs involved an analysis of their structure, composition, and optical properties, primarily conducted through X-ray diffraction (XRD) analysis. The XRD pattern conclusively confirmed the presence of the hexagonal phase in the CuS particles, a result corroborated by the accompanying Raman spectrum. The investigation further determined an estimated bandgap energy of 2.05 eV for the slightly sulfur-rich CuS NPs. Notably, this energy value exceeds that of bulk CuS (1.85 eV), indicating a noticeable miniaturization effect. The novel CuS NPs exhibited outstanding photocatalytic activity in the degradation of methyl Red (MR), particularly under visible light. This impressive performance is attributed to surface-bound OH ions on the CuS nanostructures, facilitating the adsorption and acceleration of the degradation process for MR molecules under visible light irradiation. The research presented in this article highlights the significant promise and efficiency of the synthesized CuS NPs as photocatalysts. These nanoparticles are particularly responsive to stable visible light, making them highly suitable for purifying chemically contaminated wastewater. Specifically, their effectiveness in degrading stable azo dyes, exemplified by MR, underscores their potential in practical applications.
 

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The crystallization behavior and photocatalytic properties of the sol-gel derived glass ceramic coatings in the TiO₂-SiO₂-B₂O₃ system were studied. the prepared sol was sprayed on a glazed ceramic wall. Following drying, the coated specimens were fired at 900°C for 1 h. The impact of boron oxide content in the composition was explored in terms of anatase stability and glass maturing temperature. The thermal and crystallization behaviors of the dried gels were studied by the STA, XRD, and FESEM. The photocatalytic property of the coated layer was examined using methylen blue degradation. Based on the results, the sample containing 15 wt% of boron oxide demonestrated about  30% dye removal efficiency, after only 60 min of UV-irradiation. Additionally, this particular sample exhibited the greatest magnitude of the anatase phase in comparison to the other samples.
 

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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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Heterostructure photocatalyst of CuWO₄ modified SnO₂ (CuWO₄/SnO₂) was fabricated by in simple wet-impregnation process and evaluated via degradation of rose Bengal (RB) under visible light irradiation. The samples had been completely characterized by Ultraviolet-visible diffuse reflectance spectroscopy (UV-vis-DRS), X-ray diffraction (XRD), Scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), High-resolution TEM (HR-TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett and Teller surface analysis (BET). The result divulged that amongst the catalysts, CuWO₄/SnO₂ displayed higher photocatalytic activity than CuWO₄ or SnO₂. The enhanced photocatalytic efficiencies are attributed to the charge transfer from SnO₂ to CuWO₄ nanoparticles, which efficiently decrease electron-hole recombination energy level. The time required for maximum degradation of rosebengal (RB) under visible light over CuWO₄/SnO₂ was 180 min. The other parameters such as pH (pH=8), photocatalyst dosage (0.2 g/L) and dye concentration (20 µM) were optimized to achieve high degradation efficiency (98.5%). The excellent photocatalytic activity of CuWO₄/SnO₂ is due to efficient separation of photogenerated electron-hole pairs. The holes (h⁺) and superoxide radicals (O₂^•-) are the reactive species involved in photocatalytic mechanism for gdegradation of RB.

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The present work deals with the hot deformation behavior of commercial Nb alloy C-103 and its microstructure evolution during uniaxial compression tests in the temperature range of 700-1100 °C and the strain rate range of 0.001-0.4 s^-1. Strain rate sensitivity, calculated from the compression tests data, was almost constant and showed a negative value in the temperature range of 700-900 °C but increased significantly beyond 900 °C. Dynamic strain aging was found to have a predominant effect up to 900 °C, beyond which dynamic recovery and oxidation influenced the compressive properties. The microstructure of the deformed samples showed indications of dynamic recrystallization within the high strain rate sensitivity domain and features of flow instability in the regime of low strain rate sensitivity. The 950–1000 °C temperature range and strain rate range of 0.001-0.1 s-1 were suggested as suitable hot deformation conditions. The constitutive equation was established to describe the alloy's flow behavior, and the average activation energy for plastic flow was calculated to be 267 kJ/mol.
 

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In this research, Lanthanum (La)-doped Strontium Titanate (STO) with the formula of Sr_1-xLa_xT_iO₃ (LSTO; x=0, 0.03, 0.05, and 0.07) powders have been successfully fabricated by co-precipitation route. The impacts of La³⁺ on the structural, microstructure, band-gap, and photocatalytic activity for the degradation of organic pollutants, in this case, methylene blue, under UV exposure, were reported in detail. The formation of undoped and La-doped STO samples with cubic perovskite structures was confirmed by X-ray Diffraction (XRD) results. The presence of La doping affected the microstructure morphology by producing LSTO powders with a larger specific surface area. Besides, the UV absorption of the LSTO powders was enhanced due to the narrowed band gap caused by La³⁺ dopants. Accordingly, an improvement in photocatalytic activity applied for the photodegradation of methylene blue solution was exhibited by the LSTO samples.

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In this study, the hot deformation and dynamic recrystallization behavior of low carbon steel containing 21 ppm boron was investigated. After homogenizing the samples at 1250 ℃ for 1-hour, hot compression tests were conducted at temperatures ranging from 850 ℃ to 1150 ℃ and strain rates from 0.01 to 10 s⁻¹, resulting in strain-stress flow curves. Following corrections, calculations and modeling were performed based on Arrhenius equations. Among them, the hyperbolic sine relationship provided the most accurate estimate and was selected as the valid model for the applied strain range. According to this model, the deformation activation energy (Q), was determined to be 293.37 KJ/mol. Additionally, critical and peak stress and strain values were obtained for each temperature and strain rate, and power relationships were established to describe their variation with respect to the Zener-Hollomon parameter (Z). Recrystallization fractions were derived by comparing the hypothetical recovery curves with the material flow curves, and the results were successfully modeled using the Kolmogorov-Johnson-Mehl-Avrami (KJMA) equation. The Avrami exponent was measured at approximately 2, indicating that nucleation predominantly occurred at grain boundaries. Microstructural analysis revealed that at higher Z values, recrystallization occurred along with a fraction of elongated grains, while lower Z values resulted in a greater fraction of equiaxed dynamic recrystallization (DRX) grains. The average grain sizes after compression tests at 950 ℃, 1050 ℃, and 1150 ℃ were measured as 21.9 µm, 30.4 µm, and 33.6 µm respectively at a strain rate of 0.1 s⁻¹, and 17.7 µm, 28.7 µm, and 31.3 µm at 1 s⁻¹. The overall microstructure displayed a more uniform grain size distribution with increasing deformation temperature.

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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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The investigation of SUP9 steel under the hot-rolling conditions for applications to leaf spring suspension focused on its tensile and fatigue crack growth (FCG) properties. In order to investigate the tensile properties, tensile specimens were fabricated in the longitudinal-transverse (LT) direction. Furthermore, in order to evaluate fatigue crack growth (FCG) behaviour, compact tensile (CT) specimens with different crack plane orientations in both the LT and transverse-longitudinal (TL) directions were employed. Microstructural and fractographic analyses were conducted using optical microscope (OM) and scanning electron microscopy (SEM). The hot-rolling process reduced the interlamellar spacings of Fe₃C, enhancing the tensile properties through strain hardening. A high yield-to-ultimate strength ratio (~0.623) indicates excellent plastic deformation capability and resistance to fatigue crack growth, making SUP9 steel suitable for the leaf spring suspension system. Furthermore, the exponential crack growth rate constant, m, was found to be 3.066 in the TL direction and 3.265 in the LT direction, indicating that cracks propagate more rapidly in the LT orientation. Additionally, non-metallic inclusions, such as spherical oxides and MnS precipitates in LT specimens, were observed to facilitate faster crack growth in the transverse direction.
 

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In this study, a novel three-step method for the synthesis of ZnO and branched ZnO microrods was developed. Numerous techniques were used to analyze the obtained samples: photoluminescence (PL) spectroscopy, raman spectroscopy, fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-rays (EDX), ultraviolet-visible spectroscopy (UV-visible) and X-ray diffraction (XRD).  The XRD study and Rietveld refinement confirmed that the synthesized samples have the hexagonal wurtzite structure of ZnO without any impurity with the P6₃mc space group. To further verify our experimental results, structural parameters were calculated by First Principles Density Functional Theory (DFT) calculations and compared with experimental ones. A small decrease in the unit cell volume following the branching process was observed by the DFT calculations and Rietveld refinement results. Raman spectra showed peaks corresponding to the phonon modes of hexagonal wurtzite ZnO, which was consistent with the results of XRD and Rietveld refinement. SEM confirmed that ZnO and BZnO samples have hexagonal rod and branched rod shapes. BZnO showed stronger green PL emission but lower overall PL intensity compared to ZnO. The reduced photoluminescence (PL) intensity across all frequencies indicates enhanced separation of the photogenerated electron-hole pairs in branched ZnO (BZnO) due to decreased recombination.