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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.
Manjunath Vatnalmath, Virupaxi Auradi, Bharath Vedashantha Murthy, Madeva Nagaral, Veeresh Kumar G B, Suresh Shetty, Suresh Shetty,
Volume 22, Issue 2 (6-2025)
Abstract
Dissimilar joints of AA2219 and Ti-6Al-4V alloys are obtained using the vacuum diffusion bonding method. The bonding pressure is controlled in the range of 1-4 MPa by keeping the bonding temperature and holding time constant. The influence of the bonding pressure on the microstructure and mechanical properties of the bonding joints is investigated. The diffusion behaviour across the interface of the bonding joints is increased with the increase in bonding pressure. The interface morphology of the specimen bonded at lower bonding pressures exhibits scraggly voids and cracks. The irregular voids and cracks are squeezed and gradually closed due to the significant increase in the diffusion between Al and Ti. The maximum shear strength of 81 MPa is obtained for the joint made at the bonding pressure of 4 MPa, and a diffusion layer of 0.76 µm is formed at the Ti side interface. The fracture morphology inferred the brittle failure of the bonding joints due to the formation of intermetallic compounds like TiAl, TiAl2, and TiAl3 at the interface of Al and Ti.
Uglal Pandit Shinde, Somnath Bhika Handge, Dharma Kisan Halwar,
Volume 22, Issue 2 (6-2025)
Abstract
This study investigates the effect of SnO2 as an additive on the structural, electrical, optical, and gas sensing properties of LaCrO3 nanoparticles. SnO2 is added into the LaCrO3 by weight percentage (1 wt. %, 3 wt. %, 5 wt. %, 7 wt. %, 9 wt. % and 11 wt. %) employing screen printing method. Initially, the nanoparticles of SnO2 and LaCrO3 separately synthesis by sol-gel method and then used for the development of thick films. LaCrO3 is used as host material while SnO2 is additive material. The structural characterizations like FESEM, EDX and XRD were carried out to investigate the morphology, elements and crystallite size respectively. The inclusion of SnO2 modifies the crystalline structure and surface morphology of LaCrO3, as revealed by structural analyses. The optical characterizations like FTIR and UV were used for the study of impact of SnO2 additive on functional group and band gap of the host material respectively. Optical studies indicate a modification in the bandgap, affecting light absorption properties and indicating changes in electronic transitions. The electrical characterizations were conducted by using half bridge method. Electrical resistivity measurements show enhanced performance, likely due to variation in charge carrier mobility induced by the SnO2 additive. Among other selected wt. % SnO2 additives, 9 wt. % SnO2 added LaCrO3 thick films shows maximum sensitivity to CH4 gas at 120oC operating temperature. The gas sensing characteristics demonstrate enhanced sensitivity, selectivity, and response time to target gases, suggesting that SnO2 doping improves the sensing capabilities of LaCrO3 nanoparticles, making them more efficient as a gas sensor. Obtained findings suggest that, SnO2 as an additive enhances the multifunctional properties of LaCrO3 nanoparticles, making them promising candidates for advanced gas sensing applications.
Seyed Hossein Razavi, Amirhossein Riazi, Alireza Khavandi, Mostafa Amirjan, Mohsen Ostad Shabani, Hossein Davarzani, Yazdan Shajari,
Volume 22, Issue 2 (6-2025)
Abstract
Additive manufacturing (AM) of metallic parts has gained significant attention in recent years due to its ability to produce components without traditional tooling such as molds, melting furnaces, or extensive raw material preparation. Its unique capability to fabricate complex geometries has revolutionized part design and enabled substantial weight reduction. This review first outlines the development trajectory of metal-based AM, with a particular focus on laser-based fusion methods, including Laser Powder Bed Fusion (LPBF) and Direct Laser Deposition (DLD). Understanding this evolution helps researchers identify both the capabilities and limitations of AM technologies, thereby enhancing their application in areas such as prototyping, mass production, and repair. Each metal possesses unique physical and chemical properties, which often make traditional manufacturing methods more challenging—especially for alloys with high strength, hardness, or temperature resistance. In this context, the review then focuses on nickel-based superalloys (NBSAs), which are widely used in high-temperature and high-stress environments but are particularly difficult to process using conventional techniques. Their application serves as a representative case study for evaluating the performance and feasibility of AM techniques for advanced materials. Furthermore, the future prospects of AM are discussed, including advancements in monitoring systems, integration of machine learning, and the development of AM-specific alloys. As a novel aspect, this work compares LPBF and DLD in terms of their advantages, limitations, and resulting material properties, along with a comparison to traditional manufacturing methods such as casting and wrought processing.
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.
Mahdi Rajaee, Mahdi Raoufi, Zeinab Malekshahi Beiranvand, Abbas Naeimi,
Volume 22, Issue 2 (6-2025)
Abstract
This research explored the impact of the nickel-to-manganese ratio and the influence of the matrix phase on the properties of W-Ni-Mn tungsten heavy alloys (WHAs), aiming to determine the optimal composition for achieving desirable alloy properties. For this purpose, tungsten, nickel, and manganese powders with specified weight percentages underwent two rounds of wet milling. Powder mixtures were obtained with weight ratios of 90W-6Ni-4Mn, 90W-8Ni-2Mn, and 88W-10Ni-2Mn. These mixtures were then compressed through the cold pressing method at a pressure of 250 MPa. Subsequent reduction and sintering processes were carried out in a tube furnace at temperatures of 1150 and 1400 °C, respectively. Microstructural characterization was conducted using both optical and electron microscopy. The results showed that the change in chemical composition is not significantly effective on the sintering density of the samples and also the highest sintering density, reaching 90.11%, was achieved with the 88W-10Ni-2Mn sample. Furthermore, the results demonstrated that carburization of W-Ni-Mn WHAs during the sintering process led to an increase in the micro-hardness of the samples. The highest hardness, measuring 381 Hv, was observed in the 90W-6Ni-4Mn alloy, where carburization occurred. XRD results revealed that an increase in the nickel-to-manganese ratio led to a reduction in the peaks of manganese carbide and tungsten carbide. Consequently, this decrease in carbide peaks resulted in a reduction in hardness, reaching 352 Hv in the case of the 88W-10Ni-2Mn sample. Additionally, the alloys 90W-6Ni-4Mn and 88W-10Ni-2Mn both exhibited the lowest continuity, a value of 0.5. Fracture surface SEM images illustrated that the 90W-6Ni-4Mn alloy, characterized by the lowest nickel-to-manganese ratio (1.5), exhibited the highest trans-granular fracture mode involving cleavage and matrix tearing, which is considered desirable. Furthermore, an increase in the matrix phase content resulted in a shift of the preferred crack path, originating from the matrix phase.
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.
Ines Dhifallah, Faten Rhouma, Imen Saafi, Jamila Bennaceur, Wafa Selmi, Wissem Dimessi, Radhouane Chtourou,
Volume 22, Issue 2 (6-2025)
Abstract
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.
