Showing 398 results for Co
Mehdi Mehranian, Hajar Ahmadimoghadam,
Volume 21, Issue 4 (12-2024)
Abstract
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.
Nazli Aharipour, Adrine Malek Khachatourian, Ali Nemati,
Volume 21, Issue 4 (12-2024)
Abstract
Fe3O4 nanoparticles (NPs) with a continuous and mesoporous silica (m-SiO2) shell were synthesized using a one-step method, sourcing silica from rice husk ash (RHA). The rice husk was thermally treated to obtain ash, from which silica was extracted as sodium silicate and precipitated by pH reduction. This silica powder, combined with iron chloride salts, facilitated the synthesis of the core-shell NPs. Mint extract acted as a capping agent to prevent agglomeration, and CTAB (cetyltrimethylammonium bromide) was used to create the porous SiO2 shell. X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) characterization investigated the structure, size, and shell formation. Coating integrity and suspension stability were assessed through Fourier transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS). DLS analysis showed a relatively narrow particle size distribution with an average hydrodynamic size of 72.6 nm. Small-angle X-ray scattering (SAXS) provided insights into the meso- and nanoscale structure, while BET and nitrogen adsorption-desorption isotherms confirmed the mesoporous nature of the silica shell. Magnetization measurements showed superparamagnetic behavior, with specific magnetization values of 57.9 emu/g for Fe3O4 and 27.5 emu/g for Fe3O4@m-SiO2. These results confirm the successful synthesis of superparamagnetic magnetite NPs with a mesoporous silica coating from RHA.
Maryam Hajiebrahimi, Sanaz Alamdari, Omid Mirzaee,
Volume 21, Issue 4 (12-2024)
Abstract
Dual nanocomposites based on metal sulfide nanomaterials with a narrow band gap are favorable candidates for future optoelectronic applications and ionizing ray sensors. In this study, novel silver-doped zinc sulfide/ cadmium sulfide (ZnS/CdS: Ag) nanocomposites were synthesized using the cost-effective solvothermal approach. For the first time, the radiation sensitivity of the newly developed nanocomposite was assessed using a 241Am alpha source and ion beam-induced luminescence (IBIL) measurements. The ZnS/CdS: Ag nanocomposite demonstrated significant light emission in the blue-green spectrum when measured at room temperature. When exposed to alpha irradiation, the ZnS/CdS: Ag nanocomposite film displayed exceptional sensitivity compared to pure ZnS or CdS films. The FESEM images revealed a uniform distribution of semi-spherical and rod-shaped nanoparticles, with an average particle size measuring 180 nm. The results from XRD and EDX demonstrated distinct peaks corresponding to ZnS, CdS, and associated elements within the nanocomposite. The existence of several groups within the nanocomposite was confirmed through Fourier transform infrared spectroscopy. Evaluations revealed that the optical quality of the ZnS/CdS: Ag nanocomposite showed enhancement in comparison to pure ZnS and CdS. The results suggest that the ZnS/CdS: Ag nanocomposite film holds great promise for applications in optoelectronic devices and detection technologies.
Zahra Ghoreishy, Bijan Eftekhari Yekta,
Volume 21, Issue 4 (12-2024)
Abstract
ZrO2 is commonly incorporated into ceramic glass substrates to enhance radiopacity, mechanical strength, and chemical durability. Experience has shown that the crystallization of tetragonal zirconia in glass will have a greater effect on the mechanical properties of ceramic glass. To achieve optimal properties in zirconia, stabilizing oxides are often added to enhance its structural and mechanical qualities. In this research, in order to stabilize the tetragonal phase of zirconia, MgO and CeO2 were added to the glass ceramic composition of the Li2O-SiO2-ZrO2 system and the desired dental substrate was synthesized through the sinter process. The behavior of sintering and crystallization of basic and optimized glass was investigated using HSM and DTA thermal analysis, respectively. The results showed that the optimal sinter temperature, heat press and heat treatment are equal to 730°C, 900°C and 825°C, respectively. Then, in order to determine the crystallization behavior of the prepared samples, X-ray diffraction and microstructure images were used. The results also showed that the presence of the main Li2ZrSi6O15 phase crystallizes at a temperature of 825°C in the base sample and the sample containing ceria. Also, due to early formation of MgSiO3 crystals, magnesia prevents sintering and formation of Li2ZrSi6O15 phase and stability of tetragonal zirconia phase. In the sample containing ceria, during crystallization, ZrO2 entered its crystal structure and led to the stability of the tetragonal zirconia phase at room temperature.
Zeinab Abbasali Karajabad, Adrine Malek Khachatourian, Mohammad Golmohammad, Ali Nemati,
Volume 22, Issue 1 (3-2025)
Abstract
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.
Adil Kadum Shakir, Ebrahim Ghanbari-Adivi, Aref S. Baron Baron, Morteza Soltani,
Volume 22, Issue 1 (3-2025)
Abstract
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.
Amirreza Bali Chalandar, Amirreza Farnia, Hamidreza Najafi, Hamid Reza Jafarian,
Volume 22, Issue 1 (3-2025)
Abstract
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.
Mohammad Derakhshani, Saeed Rastegari, Ali Ghaffarinejad,
Volume 22, Issue 1 (3-2025)
Abstract
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.
Amin Rahiminejad, Mojgan Heydari, Fariba Tajabadi,
Volume 22, Issue 1 (3-2025)
Abstract
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.
Shatha Batros, Farqad Rasheed, Hussein Hussein,
Volume 22, Issue 1 (3-2025)
Abstract
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.
Ahmed Kharmouche,
Volume 22, Issue 1 (3-2025)
Abstract
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.
Sumrit Mopoung, Khachidapron Seeoon,
Volume 22, Issue 2 (6-2025)
Abstract
Activated carbon preparation from tamarind wood derived charcoal by microwave-assisted sodium chloride activation was studied to investigate the effects of 0-5 wt.% NaCl and 450-850 W microwave heating power. The properties of the derived products were analyzed by FTIR, XRD, SEM-EDS, and BET. Methylene blue adsorption by the activated carbon products was also studied to evaluate the contract time, pH, methylene blue concentration, and adsorption isotherms. The study’s results showed that the percent yields (77.42-92.52%) of the fabricated activated carbons decrease with increasing wt.% of NaCl and MP. On the other hand, the contents of disordered graphitic carbon, carbonate, basic surface functional groups, and mesopores increased. However, 3 wt.% NaCl and 600 W microwave irradiation power were identified as appropriate conditions for activation, which created the micro-mesopore (pore size range 1.59 -14.76 nm) on the surface of the derived activated carbon products. Optimal values of equilibrium time and pH for methylene blue adsorption are 60 minutes and 8, respectively. The results of methylene blue concentrations were fitted to the Langmuir isotherm indicating 33.33 mg/g as the maximum methylene blue adsorption capacity.
Divya Tripathy, Anita Kushwaha, Smrita Singh, Smriti Dwivedi, Anjali Gupta, Lalit Prasad, Ashutosh Chauhan,
Volume 22, Issue 2 (6-2025)
Abstract
Organosilicon compounds represent a fascinating class of molecules with diverse structures, unique bonding characteristics, and wide-ranging applications across various fields. The structural diversity of organosilicon compounds arises from the versatility of silicon, which can form a variety of chemical bonds, including single, double, and triple bonds with carbon, as well as bonds with other heteroatoms such as oxygen, nitrogen, and sulfur. This diversity enables the synthesis of an extensive range of organosilicon molecules, including silanes, siloxanes, silanols, silazanes, and silsesquioxanes, among others. The unique properties of these compounds, such as thermal stability, chemical inertness, and flexibility, make them valuable building blocks for the design of advanced materials.Organosilicon compounds find applications in diverse fields, including materials science, pharmaceuticals, electronics, and agriculture. In materials science, they are used as coatings, adhesives, sealants, and modifiers to impart desirable properties such as water repellency, thermal resistance, and biocompatibility. In the pharmaceutical industry, organosilicon compounds serve as drug delivery agents, imaging agents, and synthetic intermediates due to their biocompatibility and tunable properties. In electronics, they are employed as dielectric materials, insulators, and encapsulants in semiconductor devices. Current review aims to unlock new opportunities for the development of innovative materials and technologies with enhanced performance and functionality.
Zainab Dhyaa Fawzy, Saja Ali Muhsin, Taha Hassan Abood,
Volume 22, Issue 2 (6-2025)
Abstract
Ceramics in dentistry have been mainly recommended from a cosmetic perspective. Yet, the hardness behaviour may limit the application in many cases. Although amber glass is used for medications and chemicals, no studies focus on using amber glass for dental purposes as an additive material. This study aims to investigate the dark amber glass behaviour as a new additive material for dental ceramics. The amber glass powder was prepared using the ball mill technique. For the amber glass powder characterization, the SEM/EDX, particle size, DSC, Ion release, and XRD analysis were tested compared to VITA Lumex® AC ceramic. In addition, the Vickers hardness test was applied for ceramic and ceramic amber with an addition of 0.01g, 0.03g, and 0.05g amber glass powder following the DIN EN ISO 6872/ 2019. Statistically, the ANOVA (post hoc- Tukey) test was used for hardness testing analysis at a significant P-value of (P≤0.05). The results show that the amber glass behaviour and composition elements seem similar to VITA ceramics. The addition of amber glass powder to ceramic shows an increase in the HV hardness of specimens. Overall, it was concluded that the amber glass powder could be a promising material for ceramics to use as an additive powder.
Ali Keramatian, Mohammad Hossein Enayati, Fatemehsadat Sayyedan, Sima Torkian,
Volume 22, Issue 2 (6-2025)
Abstract
The aim of this study was to investigate the effect of current density on the microstructure of electrodeposited Ni–WC–TiC composite coatings on 304 stainless steel and compare the corrosion resistance of the coating and substrate in a 3.5 wt.% sodium chloride solution. A Watts nickel bath was employed under direct current (DC) conditions. Microstructure, elemental composition, and phase composition analyses were conducted using scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The results revealed that the coating formed at a current density of 40 mA/cm² exhibited a denser microstructure with higher cohesion and uniformity compared to coatings produced at other current densities. The corrosion resistance of the coating and substrate was evaluated using Tafel and electrochemical impedance spectroscopy (EIS) analyses. The corrosion test results indicated that the substrate exhibited superior corrosion resistance compared to the coating. Based on the dynamic polarization test plots, the corrosion mechanism of the substrate is active-quasi passive, with a pseudo-passive layer forming on the sample which remains stable within the potential range of -0.17 to 0.17 V. Beyond this potential range, the sample becomes susceptible to pitting. In the coated sample, the corrosion behavior is similar to that of the substrate, with the exception that the pseudo-passive layer remains stable within a narrower potential range of -0.19 to 0.08 V.
Nur Aziah Suhada Naim, Muhammad Faiq Abdullah, Sung Ting Sam, Wan Ahmad Radi Wan Ahmad Yaakub,
Volume 22, Issue 2 (6-2025)
Abstract
Despite being an effective material for food packaging, chitosan (CS) exhibited poor ductility when processed into film, which restricted its use in this industry. In this study, composite films with enhanced properties were developed by incorporating polyvinyl alcohol (PVA) into CS through a simple solution casting method. The effects of different PVA/CS weight ratios (70:30, 50:50, and 30:70 w/w) on the morphology, mechanical properties, antibacterial activity, and soil degradation of the composite films were analyzed. Compared to the pristine PVA film, increasing the CS content in the PVA/CS composite film enhanced thickness, stiffness, roughness, antibacterial efficiency, and degradation rate, while reducing tensile strength and elongation at break. Fourier transform infrared (FTIR) spectroscopy revealed the highest intermolecular interactions in the PVA/CS composite film with 70:30 w/w. Antibacterial activity tests and soil burial analysis demonstrated that the PVA:70/CS:30 composite exhibited significantly higher antibacterial activity toward Escherichia coli and Bacillus subtilis bacteria as opposed to PVA film, along with a moderate degradation rate of 76.76% following 30 days soil burial, effectively balancing biodegradability and material integrity. These findings suggest that the PVA:70/CS:30 composite is a promising alternative for sustainable and functional biodegradable packaging solutions.
Amin Rezaei Chekani, Malek Naderi, Reza Aliasgarian, Yousef Safaei-Naeini,
Volume 22, Issue 2 (6-2025)
Abstract
This paper presents the novel fabrication method of a three-dimensional orthogonally woven (3DW) C/C-SiC-ZrB2 composite and the effects of ZrB2 and SiC particles on microstructure and the ablation behavior of the C/C–SiC–ZrB2 composite are studied. C/C–SiC–ZrB2 composite was prepared by isothermal-chemical vapor infiltration (I-CVI), slurry infiltration (SI), and liquid silicon infiltration (LSI) combined process. Pyrolytic carbon (PyC) was first infused into the 3DW preform by I-CVI at 1050°C using CH4 as a precursor in order to form a C/C preform with porous media. The next step was graphitization at 2400°C for 1hr. Then ZrB2 was introduced into 3DW C/C preform with a void percentage of 48 by impregnating the mixture of ZrB2 and phenolic resin, followed by a pyrolysis step at 1050°C. A liquid Si alloy was infiltrated, at 1650 °C, into the 3DW C/C composites porous media containing the ZrB2 particles to form a SiC–ZrB2 matrix. An oxyacetylene torch flame was utilized to investigate The ablation behavior. ZrB2 particles, along with the SiC matrix situated between carbon fiber bundles, form a compact ZrO2-SiO2 layer. This layer acts as a barrier, restricting oxygen infiltration into the composite and reducing the erosion of carbon fibers. The findings were supported by FESEM imaging and further confirmed through x-ray diffraction and EDS analysis. The addition of ZrB2 to the C/C-SiC composite resulted in a lower mass and linear ablation rate; 2.20 mg/s and 1.4 µm/s respectively while those for C/C-SiC composite were 4.8 mg/s and 6.75 µm/s after ablation under an oxyacetylene flame (2500°C) for 120 s.
Sara Ahmadi, Bijan Eftekhari Yekta, Alireza Mirhabibi, Sara ,
Volume 22, Issue 3 (9-2025)
Abstract
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.
Gajanan M Naik, Santhosh Kumar B M, Shivakumar M M, Ramesh S, Maruthi Prashanth B H, Gajanan Anne6,
Volume 22, Issue 3 (9-2025)
Abstract
Magnesium and the alloys made from the same metal are utilized in the engineering applications such as automotive, marine, and aircraft, among others due to high strength to weight. Nevertheless, the applications of magnesium alloys are currently limited to a certain level due to their poor wear and corrosion properties. Another effective strategy for enhancing these properties involves utilizing the process of equal channel angular extrusion (ECAE), which serves to refine the grain structure, thereby resulting in improved material properties. This paper aims to establish the relationship between grain size reduction and wear and corrosion of AZ91 alloy. The wear performances of both coarse-grained and fine-grain alloy were conducted using L9 orthogonal array of experiments in order to study the effects of control parameters on wear performance. In the study, it has also been identified that through ECAP, the corrosion barrier and wear characteristics of the alloy were enhanced due to fine-grain-structure and the spheroidal precipitation of the second β-phase particles. Further, the influence of these changes on the performance of the AZ91 Mg alloy was assessed using SEM.
Azam Bayat,
Volume 22, Issue 3 (9-2025)
Abstract
The lindgrenite compounds [Cu3(MoO4)2(OH)2] with various architectures and high crystallinity were prepared by a simple surfactant-assisted hydrothermal method. Then, the Cu3Mo2O9 samples were prepared by calcination of the as-synthesized Cu3(MoO4)2(OH)2. The resulting samples had high crystallinity, colloidal properties, high-yield, large-scale production capability with using of nontoxic and inexpensive reagents and water as an environmentally solvent. The scanning electron microscope studies showed that the as-prepared lindgrenite nanostructures were well crystallized with rod, sheet and hollow sphere morphologies. These products were content of the Cu3(MoO4)2(OH)2 rods with diameters of about 100 nm, the Cu3(MoO4)2(OH)2 nanosheets with thickness of 30–100 nm and the Cu3(MoO4)2(OH)2 hallow spheres, consisting of a large number of nanosheets with thickness of about 40-70 nm. The Cu3Mo2O9 samples that obtained by thermal treatment of lindgrenite retained the original morphologies. Meanwhile, the photoluminescence and magnetic properties of the nanosheet samples showed super paramagnetic behavior at room temperature and in comparison with previous works, Cu3(MoO4)2(OH)2 and Cu3Mo2O9 samples synthesized by the surfactant-assisted hydrothermal method had a very obvious red-shifted PL emission and high intensity.
