Iranian Journal of Materials Science and Engineering

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In this study, an epoxy-based nanocomposite reinforced with copper oxide-graphene oxide hybrid was investigated. Initially, the hybrid powder of CuO–GO with a weight ratio of 9:1 was prepared. The hybrid filler with different weight percentages ranging from 0.1–0.5 was used to reinforce the epoxy resin. The prepared samples were analyzed using XRD, FTIR, FESEM, TEM, and tensile testing. According to the XRD results and SEM images, the hybrid powder was successfully prepared, and the mechanical testing results showed an improvement in tensile strength in the composite samples. The best composite sample in terms of tensile strength was the one containing 0.3 wt% of hybrid reinforcement, which exhibited a 73% increase in strength compared to the neat resin sample.

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The present work deals with the effect of Multi-walled Carbon Nanotube (MWCNT) and functionalized (carboxyl and amine) MWCNT on the mechanical properties of the PAEK (Poly Aryl Ether Ketone) polymer composite. The MWCNT and functionalized (carboxyl and amine) MWCNT concentration varied as 0.25, 0.5 and 0.75 weight percentages. Compositeswere prepared by using a melt compounding method using a twin-screw extruder and all testing samples were prepared using an injection molding machine as per American Society for Testing and Materials (ASTM) standards. Samples were tested for tensile strength, impact strength, flexural strength, heat deflection temperature, hardness, and density. There is an increase in the tensile strength, impact strength, flexural strength, and heat deflection temperature, with percentage increase in filler loading up to 0.5 %, followed by decrease in it with higher filler loading. The increase is maximum for amine functionalized MWCNT.

 

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Perovskite materials are widely studied for their super-conducting, magnetic, catalytic and electro-optic properties. Among them, barium stannate (BaSnO₃), finds applications in dielectric and optically active devices, thermally stable capacitors, humidity and gas sensors. In this study, BaSnO₃ was synthesized by chemical and greener methods and comparative analyses has been performed on their electrochemical, third order nonlinear, dye deactivation and bacterial suppression properties. Decreased crystallite size was realized for the green synthesized BaSnO₃. Energy band gaps were 3.23 and 3.04 eV for BaSnO₃ synthesized by normal and greener approach, respectively. The extract mediated sample exhibited increased specific capacitance value. Photocatalytic degradation efficiencies were 78.4% and 89.7%, respectively for BaSnO₃ synthesized by normal and greener approach against methyl violet after 90 min of UV light irradiation. Enhanced nonlinear optical parameters were obtained for the extract mediated BaSnO₃. Excellent antibacterial efficacy against Proteus vulgaris bacteria was realized for the greener BaSnO₃ NPs thanks to the domination of phytochemicals of M. olifera leaf extract.
 

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In this work, the effect of variation of the non-ideality coefficient of the p-n-junction volt-ampere (I-V) characteristic located in the strong microwave field on the differential resistance, diffusion capacitance and differential conductance is studied. Here, it is shown that the p-n junction I-V characteristics increases with the value of the non-ideality coefficient, whether the differential resistance is in a strong microwave field or a weak microwave field. Diffusion capacitance and differential conductance are shown to decrease with increasing value of non-ideality coefficient.
 

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Celestite ore, the primary mineral for producing strontium compounds, particularly strontium carbonate, is processed using the black ash method, which involves carbothermic reduction, water leaching, and carbonation. This study aims to investigate the combined effect of mechanical activation and additional graphite on the recovery rate and purity of strontium carbonate. Celestite ore with a strontium sulfate content of 79% was obtained from the Dasht-e-Kavir mine. Acid washing with 10% hydrochloric acid significantly reduced carbonate impurities, resulting in a celestite purity of 96.9%. Mixtures of celestite and graphite with varying amounts of graphite were prepared with and without milling. The mixtures were roasted at 900 °C for 1 hour to form strontium sulfide, followed by hot water leaching. After filtration, sodium carbonate was added to the leachate containing SrS, resulting in the formation and precipitation of white strontium carbonate crystals. The results showed that the addition of graphite increased the recovery rate in unmilled specimens. However, the recovery rate decreased significantly when 1 and 10 hours of milling were applied in the presence of excess graphite. Conversely, in the absence of additional graphite, milling for 1 and 10 hours increased the strontium recovery rate to over 95%. Furthermore, the analysis of strontium carbonate obtained from the sample with the highest recovery rate showed a purity of over 99.9%.

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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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Natural-reinforced hybrid composites, called "eco-materials," are becoming increasingly important for protecting the environment and eliminating waste problems. In this study, hybrid biocomposites were produced by the colloidal mixing method using seashell (SS) as natural waste, two graphene derivatives (graphene oxide (GO) and reduced graphene oxide (RGO)) as filler material, and polyvinyl chloride (PVC) as the polymer matrix. The crystallization and mechanical properties of hybrid biocomposites were examined based on their thermal properties using TGA and DSC analysis. In comparison to PVC/GO and PVC/RGO composites with identical weight percentages of GO and RGO, the PVC/GO composite exhibited superior thermal stability and crystallinity, resulting in elevated hardness values for the same composite. These results were attributed to the better interaction of GO with PVC due to the higher number of oxygen-containing functional groups in GO than in RGO. However, the PVC/RGO/SS hybrid biocomposites exhibited superior properties than PVC/GO/SS hybrid biocomposites. The greatest crystallinity values were 39.40% for PVC/RGO/SS-20 compared to PVC/RGO at 20 wt% SS content and 29.21% for PVC/GO/SS-20 compared to PVC/GO. The PVC/RGO/SS-20 hybrid biocomposite showed the greatest gain in hardness value, up 18.47% compared to the PVC/RGO composite. No significant change was observed in the melting and weight loss temperatures as the SS content increased; however, the crystallinity and glass transition temperatures in hybrid biocomposites increased as the SS content increased. All analysis results demonstrated the achievement of SS-graphene-PVC interactions, suggesting that SS waste could enhance the thermal and mechanical properties of composite production.

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In this research study, a composite coating of Ni-Co/SiC-CeO₂ was prepared on a copper substrate using the pulse electrodeposition technique. The effects of electrodeposition parameters, including current density, duty cycle, and frequency, on the properties of the prepared coating were investigated. The selected current density values were 0.1, 0.2, and 0.3 A/cm², the duty cycle options were 10, 20, and 30%, and the frequency values were 10, 100, and 1000 Hz. Increasing the current density enhanced the microhardness of the coating but reduced its corrosion resistance. This behavior can be attributed to the grain refinement occurring within the coating as the current density increases. On the other hand, an increase in duty cycle resulted in a decrease in microhardness, which can be attributed to a decrease in the concentration of nanoparticles within the coating. The lower corrosion resistance observed at higher duty cycles could be attributed to the decrease in off-time, causing the pulse electrodeposition conditions to approach a DC (direct current) state. Furthermore, higher frequencies were found to be associated with increased microhardness and improved corrosion resistance of the coatings. The coatings with the highest corrosion resistance exhibited a corrosion current density of 0.29 µA/cm² and a polarization resistance of 1063 Ω.cm² in a 3.5% NaCl solution. These coatings were prepared using a current density of 0.2 A/cm², a duty cycle of 10%, and a frequency of 1000 Hz.

 

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The trimanganese tetraoxide (Mn₃O₄) nanostructured thin films doped with 2 mol % of nickel (Ni) and molybdenum (Mo) ions were deposited by a simple electrophoretic deposition technique. The structural, optical, and morphological studies of these doped thin films were compared with pure Mn₃O₄ thin films. X-ray diffraction (XRD) confirmed the tetragonal Hausmannite spinel structure. The Fourier transform infrared spectroscopy (FTIR) provided information about the molecular composition of the thin films and the presence of specific chemical bonds. The optical study and band gap energy values of all thin films were evaluated by the UV visible spectroscopy technique. The scanning electron microscopy (SEM) illustrated the morphological modifications of the Mn₃O₄ thin films due to doping of the nickel and molybdenum ions. The Brunauer Emmett Teller (BET) method has confirmed the mesoporous nanostructure and nanopores of the thin films. The supercapacitive performance of the thin films was studied by cyclic voltammetry (CV), and galvanostatic charge discharge (GCD) techniques using the three-electrode arrangement. An aqueous 1M Na₂SO₄ electrolyte was used for the electrochemical study. The 2 mol % Ni doped Mn₃O₄ thin film has shown maximum specific capacitance than pure and Mo doped Mn₃O₄ thin films. Hence, this study proved the validity of the strategy - metal ion doping of Mn₃O₄ thin films to develop it as a potential candidate for electrode material in the futuristic energy storage and transportation devices.

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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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Iron oxide nanoparticles has attracted extensively due to their supermagnetic properties, preferred in biomedicine because of their biocompatibility and potential nontoxicity to human beings. Synthesis of iron nanoparticles (FeNPs) was prepared with the help of ferric chloride and ferrous sulphate by using the coprecipitation method. The variation and combination of ferric and ferrous concentrations affect the physical and magnetic properties of iron oxide nanoparticles.  The effect of 0.1 M ferric and ferrous concentration on iron oxide nanoparticles studied separately and in combination. The obtained nanoparticles were characterized by Particle size, zeta potential, Ultraviolet (UV-visible), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscope (SEM), Thermal gravimetric analysis (TGA), and Vibrating-sample magnetometer (VSM) techniques. Particle size was below 200nm and zeta potential was within the limit for all the batches. UV visible spectra at 224 nm, and FTIR exhibit two peaks at 510 and 594 cm-1, indicating iron oxide NPs and XRD confirmed the crystalline nature of Fe. SEM showed a spherical shape for all batches. The use of a combination of ferric and ferrous is more effective than its individual use. TGA and VSM studies confirmed its magnetic properties.
 

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Drug-resistance among bacteria is a concerning issue in medical field. Silver nanoparticles (AgNPs) are one of the promising novel nano-antibiotics. In the present study, AgNPs were synthesized using cell-free extract of Acinetobacter sp. challenged with silver nitrate. Preliminary observations done using UV-Vis spectrophotometry at 420 nm. Complete reduction of silver ions to AgNPs was confirmed through cyclic voltammetry. Electron microscopy revealed formation of spherical shaped nanoparticles of size upto 20 nm. These AgNPs were furthr used to determine their effect on activity of various antibiotics against pathogenic bacteria such as Neisseria and Xanthomonas. Higher antibacterial activity of AgNPs was observed against Gram-negative bacteria. Enhanced antibacterial action of AgNPs was observed with selected beta-lactam antibiotics producing upto 3-fold increase in area of zone of inhibition. On exposure to AgNPs, the minimum inhibitory concentration and minimum bactericidal concentration of antibiotics were lowered by upto 2000 times indicating potential synergistic action of AgNPs. This study clearly signifies that the drug, proved to be inefficient due to bacterial resistance, could be made functional again in presence of AgNPs. This will help in development of novel antibacterial formulations containing antibiotics and nanoparticles to combat multiple drug-resistance in microorganisms.

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The Nickel tungsten (Ni-W) alloy was electrodeposited on stainless steel (SS) substrate using potentiostatic mode at room temperature. Potentiostatic electrodeposition was carried out by varying the deposition time. The physicochemical properties of Ni-W alloys were studied using X-Ray diffraction (XRD), Electron Microscopy and micro-Raman spectroscopy. Recorded XRD spectra was compared with standard JCPDS card and the presence of Ni was confirmed, no such peaks for W were observed. Further study was extended for micro-Raman analysis. From Raman spectroscopy study the appearance of Ni-O and W⁶⁺=O bonds confirms that the Ni-W present in amorphous phase. Several cracks were observed in SEM images along with nanoparticles distributed over the electrode surface. The appearance of cracks may be correlated with the in-plane tensile stresses, lattice strains and stacking faults and may be related to the substrate confinements.
 

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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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Nickel doped CoMn ferrites with high magnetization were synthesized by double sintering solid state route with compositions of Co_0.7-xNi_xMn_0.3Fe₂O₄ with x = 0, 0.05, 0.1 and 0.15. Theoretical Cation distribution for cubic spinel ferrites was suggested on basis of electrical configuration expectations and cation site preferences. Cation distribution suggested was in good agreement with experimental results obtained from VSM and XRD. Values of theoretically calculated magnetic moment, coercivity and magnetization are in good agreement with experimental data obtained from VSM. Maximum saturation magnetization of 37.7emu/gm is obtained for sample Co_0.7Mn_0.3Fe₂O₄ at magnetic field of 5K Oe. Magnetostriction was found to increase with increasing magnetic field (from 1KOe to 5KOe.) Maximum magnetostriction of 84ppm was observed for sample Co_0.7Mn_0.3Fe₂O₄ at 5KOe. Maximum magnetization of magnetoelectric composites with 30% Co_0.7-xNi_xMn_0.3Fe₂O₄ – 70% PbZr_0.48Ti_0.52 was found to be 7.4 emu/g for composition with x = 0.
 

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The Mn-Zn ferrite with a composition of Mn_0.25Mg_0.08Cu_0.25Zn_0.42Fe₂O₄ has been synthesized in this study using the chemical sol-gel technique at a pH of 7. The sample was prepared and subsequently annealed at a temperature of 700°C. The nanocrystalline ferrite samples were subjected to characterization using X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Thermogravimetry (TG), and Differential thermal analysis (DTA). The findings of these observations are delineated and deliberated. The sample's phase composition was verified using X-ray diffraction examination. The crystalline size was determined using Scherrer's formula and was observed to be within the range of 20-75 nm. Two notable stretching bands were seen in the FTIR spectra within the range of 400-650 cm^-1. The spinel structure of the produced nanoparticles was confirmed by these two bands. The magnetic characteristics of the powder were examined using a Vibrating Sample Magnetometer (VSM). The presence of M-H hysteresis loops suggests that the produced nanoparticles have superparamagnetic properties, as evidenced by their low coercive force, remanent magnetization, and saturation magnetization values.