Iranian Journal of Materials Science and Engineering

Investigating Electrical and Ferroelectric Properties of Nd Doped BiFeO3-PbTiO3 Solid Solutions

Ram Chhavi Sharma

The effect of different Nd and PT compositions on the electrical and ferroelectric properties of (1-y)Bi_1-xNd_xFeO₃-yPbTiO₃ solid solutions, where x = 0.05, 0.10, 0.15, 0.20 and y = 0.1, 0.2, 0.3, and 0.4, was investigated to optimise material performance. Nd doping enhances the frequency-dependent dielectric properties of produced solid solutions. However, an anomaly in the dielectric loss tangent, which is consistent with the Debye relaxation process, is observed for compositions with x˂0.10 and y≥0.2 values in the frequency range of 1 KHz to 1 MHz. Dielectric anomalies were more noticeable around the transition temperature in temperature-dependent dielectric characteristics plots, suggesting stronger magnetoelectric interactions. The decrease in the dielectric constant for solid solution compositions with y ≥0.3 indicates the presence of MPB with BFO due to an increase in the tetragonal phase of the PbTiO3 compound. As Nd content increases, temperature-dependent dielectric permittivity predicts relaxor-type ferroelectric performance for y=0.4 composition of solid solutions. A ferroelectric investigation showed that saturation polarisation, remnant polarisation, and coercive field of all prepared solid solutions decrease with increased Nd doping. However, for y˃0.3 composition, a substantial rise in these parameters was observed, which is a result of electric order dominating over magnetic order in solid solutions. The study reveals that Nd doping reduces leakage current, making it a promising contender for future applications

Investigating the Fracture Toughness and Mechanical Properties of the Two-Layer Al 1050/Mg AZ31B Sheets Fabricated by the Roll Bonding, Considering the Annealing Temperature Effect

ramin hashemi

This study presents the manufacturing of Al 1050/Mg AZ31B bimetallic sheets using the cool roll bonding process, followed by an investigation of the effect of annealing temperature on mechanical properties and microstructural features. Annealing treatment was performed at 200, 300, and 400 degrees Celsius. Mechanical testing includes tension, micro-hardness, three-point bending, and fracture toughness. Scanning electron microscopy equipped with energy-dispersive X-Ray spectroscopy (SEM-EDX) and X-ray diffraction (XRD) were used to investigate the microstructure in the infiltration zone. Mechanical testing shows that increasing the annealing temperature decreases the tensile strength of the two-layer specimens. Micro-hardness, XRD, and SEM-EDX investigations confirm the presence of intermetallic particles in the penetration zone. The Micro- hardness test showed that with the increase of the annealing temperature, the hardness in the penetration zone of Al 1050/Mg AZ31B increases. This increase in micro-hardness result confirms the presence of harder intermetallic phases with increasing annealing temperature in the penetration zone.

Cobalt Thin Films Synthesis and Structural and Morphological Pproperties

Ahmed KHARMOUCHE

Series of cobalt (Co) thin films with various thicknesses ranging from 50 to 400 nm have been fabricated using thermal heating under vacuum. We explore the impact of the thickness layer on the structural and morphological properties of the films. X-Ray diffractions and atomic force microscopy tools have been used to carry out the structural and the morphological properties of these films. The films are principally c-axis oriented, polycrystalline and with <0001> texture. The crystallites sizes have been found to range from 18.40 to 79.46 nm, and they increase with increasing thickness. The ratio c/a value indicates that Co films are subject to a tensile stress, probably because of the way the film grows. The microstrain is positive and ranges from 1.53 to 3.56%. Atomic force microscopy observations indicate the formation of crystallites according to the Stranski-Krastanov mode. The films topographical surfaces are very smooth, the average root mean square roughness ranging from 0.2 to 1.5 nm.
Keywords: Co; Thin films; XRD; Crystallite size; AFM.

Investigation of the Effect of Calcination Time on the Antibacterial, Antifungal and Anticancer Activities of TiO2/ZnO Nanocomposites

Adil Kadum Shakir

Nanomaterials have significantly transformed multiple scientific and technological fields due to their exceptional properties, which result from their quantum confinement effects and high surface-to-volume ratios. Among these materials, zinc oxide (ZnO) and titanium dioxide (TiO₂) nanoparticles have attracted considerable interest because of their diverse applications.
In this study, TiO₂-ZnO nanocomposites were synthesized using varying calcination times of 1, 1.5, 2, 2.5, and 3 hours. Characterization of fabricated samples through X-ray diffraction (XRD) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDXS) confirmed the successful fabrication of the nanocomposites. In this regard, XRD analysis revealed anatase TiO₂ and hexagonal wurtzite ZnO phases. Raman spectroscopy also supported these findings, identifying characteristic peaks of both TiO₂ and ZnO.
The calcination time had a minimal effect on the crystal structures and also morphology of the nanocomposites, which gave rise to its negligible impact on optical properties and biological activities of the samples. Optical properties assessed by means of UV-visible and photoluminescence (PL) spectroscopy showed consistent band gap absorption and emission profiles across all samples, among which the nanocomposite calcined for 1 hour exhibited the best optical properties.

The sample prepared at 1 hour not only showed the most favorable optical properties, but also demonstrated significant antibacterial, antifungal, and cytotoxic activities, which make it suitable for various applications. In this regard, a reduction of more than 99.9% occurred in the number of Escherichia coli and Staphylococcus aureus bacteria and also Candida albicans fungus by using TiO₂-ZnO nanocomposite. Besides, addition of 500 µg/ml of nanocomposite decreased the cell viability to 34.47%, which signifies its high cytotoxicity activity.

Gamma Irradiation Effects on Physical, Optical, Structural and Radiation Shielding Properties of Tellurite based Glasses

FUEI PIEN CHEE

Tellurite glasses have been researched for their radiation shielding properties as a potential alternative to lead and lead silica glass, which pose toxicity concerns. The effects of radiation on tellurite glasses are assessed using both physical irradiation and simulation with the Phy-X/PSD software. Glasses with the composition (70-x-y)TeO2–20ZnO–9Na2O–1Er2O3–(x)TiO2–(y)Al2O3, were fabricated using the melt-quench method. These glasses were then irradiated with gamma radiation at different doses. Characterization techniques, including XRD and UV-VIS spectroscopy, along with density measurements, were applied to the glasses both before and after irradiation. The XRD results confirmed that the glass samples were amorphous. UV-VIS spectroscopy showed that transmittance decreased as the radiation dose increased. The Phy-X/PSD simulation program was used to model the radiation properties of the glasses based on their dosage and composition. The simulation results indicated that the half-value layer (HVL) and mean free path (MFP) increased post-irradiation and then remained constant. These findings suggest that tellurite glasses, with their enhanced radiation shielding properties, could be a viable, safer alternative to lead-based glasses for various applications.

Investigation of Mechanical Strength and Fatigue Crack Growth Behaviour of Hot-Rolled SUP9 Steel for Leaf Spring Suspension Application

Dwi Asmi

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.

Castor Folate Ester Niosomes: Enhancing Doxorubicin Hydrochloride Delivery and Stability

Mojgan Heydari

Targeted drug delivery systems have been developed to overcome the disadvantages of conventional drug delivery systems and folate is one of the targeting molecules that has received attention in recent years. The attachment of this molecule to the surface of niosomal carriers has been achieved using Castor oil as an intermediate molecule. We synthesized caster folate (CF) and incorporate to noisome structure as biocompatible component for targeted delivery of anticancer drug Doxorubicin. This research studies the novelty of castor folate ester in the scope of niosome-based drug delivery systems. The aim was to investigate the feasibility of manufacturing and evaluating a niosomal carrier containing the drug doxorubicin hydrochloride (DOX) and its targeting by the combination of CF. The results of Fourier Transform Infrared Spectroscopy (FTIR) confirm chemical bounding between folic acid and castor oil. SEM showed good morphology with spherical structure of niosomes. These niosomes have particles size of 330 to 538 nm for different samples. Also, zeta potential was -28 to -40 mV that results good stability. The addition of CF to niosomal samples increased wettability and drug loading efficacy and along with DLS and zeta potential results confirms the folate impact on surface hydrophilicity of niosome spheres. The prepared formulations increased the effectiveness of doxorubicin on L929 fibroblast cells. The proposed biocompatible component showed the role of CF in the architectural integrity of niosomal lipid bilayers.

Effect of Pre-cold Deformation and Welding Current Mode on Mechanical Properties and Microstructure of GTAWed Nimonic 80A Superalloy

Amirreza Farnia

This study investigates the microstructural evolution and variations in the mechanical properties of pre-cold worked Nimonic 80A superalloy, subjected to two levels of deformation (25% and 50%) and welded via Gas Tungsten Arc Welding (GTAW) and Pulsed Current Gas Tungsten Arc Welding (PCGTAW) techniques using ER309L filler wire. The objective is to evaluate the effect of the initial microstructure on the welding behavior of Nimonic 80A and compare the weldments produced using GTAW and PCGTAW. Microstructural characterization was conducted using optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). XRD analysis demonstrated that the welding pulsed current mode, compared to the continuous current mode and at equal heat input, led to a refined microstructure, suggesting improved welded mechanical properties of the weld. It also showed a potential reduction in grain refinement with a higher level of cold work. Tensile testing demonstrated that fractures consistently occurred within the weld zone (WZ), with the PCGTAW sample achieving the highest tensile strength (766 MPa). Microhardness analysis indicated a notable reduction in hardness within the heat-affected zone (HAZ) and WZ, particularly in the 50% pre-cold worked sample. However, PCGTAW retained higher hardness due to its refined microstructure. The weld metal primarily consisted of an austenitic microstructure characterized by dendrites and interdendritic precipitates. Microstructural analysis revealed that welding induced significant changes in the weldment, with the PCGTAW sample exhibiting a more uniform microstructure and smoother transitions at the weld interface. Fractography confirmed ductile fracture in all specimens, with smoother and more uniformly distributed dimples in the PCGTAW sample. These findings highlight the advantages of pulsed current welding in optimizing the mechanical performance of Nimonic 80A welds and suggest its potential application in industries requiring superior weld quality.

High-Performance Hybrid Asymmetric Supercapacitors with rGO/α-Fe2O3 and rGO/TiO2 Nanocomposites

Adrine Malek Khachatourian

Hybrid asymmetric supercapacitors using distinct cathode/anode materials offer enhanced energy density by expanding operational potential windows compared to symmetric configurations. In this work rGO/α-Fe₂O₃ and rGO/TiO₂ nanocomposites were synthesized via hydrothermal method for hybrid asymmetric supercapacitors applications. Field emission scanning electron microscope (FESEM) revealed uniform distribution of spherical α-Fe₂O₃ and TiO₂ nanoparticles on rGO sheets. The X-ray diffractometry (XRD) analysis confirmed the presence of the hematite and anatase in the rGO/α-Fe₂O₃ and rGO/TiO₂ nanocomposites, respectively. Additionally, in the XRD spectra of both nanocomposites, a broad peak corresponding to the (002) crystalline planes of rGO was observed. Electrochemical testing showed specific capacities of 130 F/g (rGO/α-Fe₂O₃) and 253 F/g (rGO/TiO₂) at 5 mV/s in 1M KOH. The assembled hybrid asymmetric supercapacitors (rGO/α-Fe₂O₃//rGO/TiO₂) achieved a 1.6 V operational potential window. Power density and energy density of 1066 W kg^-1 and 9.7 Wh kg^-1 were achieved at a current density of 1 A/g, respectively.

Antibacterial Activity and Microstructure properties of Copper Oxide particles Doped with Cadmium Prepared by Chemical Precipitation Method

hussein hussein

The copper oxide nanoparticles were synthesized using a precipitation method, recognized for its significance in antibacterial applications. This study reports the synthesis of pure CuO and CuO:Cd nanoparticles at two different concentrations, and explores their structural properties and antibacterial activity. The structural characteristics of the prepared powders were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Raman spectra were also examined using a 543 nm laser wavelength. XRD analysis confirmed that the as-synthesized samples exhibit a face-centered monoclinic structure, with crystallite size decreasing as dopant concentration increases, as estimated using the Scherrer method. The obtained crystallite sizes ranged from 7.13 to 11.72 nm, likely due to the larger atomic radius of Cd compared to Cu. The major Raman lines observed included Au2 (156 cm^-1), Ag (∼294 cm^-1), Bu2 (∼598 cm^-1), and lines at 1100 cm^-1 and 1420 cm^-1. The antibacterial activity of the synthesized CuO and CuO:Cd specimens was evaluated using the Kirby-Bauer disk diffusion method against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. The antibacterial activity increased with higher Cd concentrations and smaller particle sizes, resulting in larger inhibition zones and higher percentage inhibition ratios for both types of bacteria.
The copper oxide nanoparticles were synthesized using a precipitation method, recognized for its significance in antibacterial applications. This study reports the synthesis of pure CuO and CuO:Cd nanoparticles at two different concentrations, and explores their structural properties and antibacterial activity. The structural characteristics of the prepared powders were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Raman spectra were also examined using a 543 nm laser wavelength. XRD analysis confirmed that the as-synthesized samples exhibit a face-centered monoclinic structure, with crystallite size decreasing as dopant concentration increases, as estimated using the Scherrer method. The obtained crystallite sizes ranged from 7.13 to 11.72 nm, likely due to the larger atomic radius of Cd compared to Cu. The major Raman lines observed included Au2 (156 cm^-1), Ag (∼294 cm^-1), Bu2 (∼598 cm^-1), and lines at 1100 cm^-1 and 1420 cm^-1. The antibacterial activity of the synthesized CuO and CuO:Cd specimens was evaluated using the Kirby-Bauer disk diffusion method against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. The antibacterial activity increased with higher Cd concentrations and smaller particle sizes, resulting in larger inhibition zones and higher percentage inhibition ratios for both types of bacteria.

Modification of Electrical and Optical Properties by Incorporating Mn, Ta and Nb Dopants into TiO2-based Thin layer Utilizing Powder-based Physical Vapor Deposition (PPVD) Technique

Muhammad Rizwan

Powder-based Physical Vapor Deposition (PPVD) was utilized to deposit doped TiO₂ thin layers, to modify electronic and optical properties. The modification was performed using different dopants (MnO₂, Ta₂O₅, Nb₂O₅) at different concentrations (0.05 and 0.1 mol%) respectively. The structural characterization by FESEM reveals that the size of the grain varied with respect to the dopants. The sample doped at lower concentration demonstrates a larger crystallite size than the sample doped at higher concentration. This trend is consistent with the measured grain size of the doped thin layer samples. The nonlinearity coefficient (α) and breakdown voltage at lower ranges are enhanced as the dopant concentration in the TiO₂lattice increases due to the reduction of grain size. While, the optical properties of doped TiO₂ thin layers with respect to energy bandgap demonstrated enhancement trend with the addition of the dopant as revealed by UV-Vis’s reflectance analysis. The enhancement of electrical and optical properties is contributed by the formation of barrier layer surrounding the grains, which in return increases the conductivity of the doped TiO₂ thin layers sample. Conclusively, this study demonstrates the feasibility of the PPVD method in producing a dense thin layer structure for further optical and electrical based applications.

Foam-like Electroplated Ni-W/graphene Oxide Composite Coating with High Porous Surface: An Efficient Electrocatalyst for the Hydrogen Evolution Reaction

Saeed rastegari

In this research, the morphology of the Ni-W coating was modified by adding graphene oxide (GO) nanosheets in such a way that a foam-like structure with high porosity and holes in the form of intertwined tunnels was obtained. Different amounts of GO nanosheets were added to the plating bath and the resulting coating was examined. In order to estimate the electrochemically active surface area, the cyclic voltammetry (CV) test was used. Moreover, the linear polarization test (LSV) and chronoamperometry in 1 M NaOH were conducted to investigate the electrocatalytic activity for the hydrogen evolution reaction (HER). It was found that by adding 0.4 g/L GO to the electroplating bath, the electrocatalytic properties are doubled and the active surface of the electrode is significantly increased.