Showing 758 results for Type of Study: Research Paper
Hossein Naseri, Behnam Lotfi, Zohreh Sadeghian,
Volume 22, Issue 4 (12-2025)
Abstract
Bulk titanium-based metallic glass with amorphous structure has led to the creation of special properties, which can be used as a suitable alternative to metallic biomaterials with crystalline structure. In the present study, bulk titanium-based metallic glass without Ni and Be elements produced by vacuum arc melting and cast into a 4 mm diameter mold. The evaluation of the results showed that the Ti50Zr15Cu20Mo7Ag4Sn3Si1 metallic glass has a composite structure of dispersed crystalline phases (α-Ti, β-Ti and Ti2Cu) in a glassy field. However, the Ti50Zr25Cu5Mo10Ag6Sn3Si1 alloy has a higher glass formation ability (GFA) and the crystalline phases formed in the Ti50Zr15Cu20Mo7Ag4Sn3Si1 alloy disappeared with increasing the amount of alloying elements Zr, Mo and Ag. The corrosion current (ICorr) of the Ti50Zr25Cu5Mo10Ag6Sn3Si1 alloy (43.28 nA) was lower compared to the corrosion current of the Ti50Zr15Cu20Mo7Ag4Sn3Si1 and Ti6Al4V samples (133.9 and 92.41 nA, respectively) in Hank's solution, hence the Ti50Zr25Cu5Mo10Ag6Sn3Si1 alloy showed better corrosion resistance.
Hossein Bayat, Parvaneh Sangpour, Mojgan Heydari, Leila Nikzad,
Volume 22, Issue 4 (12-2025)
Abstract
In this study, we investigated the antimicrobial, bioactivity, and in vitro cytotoxicity of a nanocomposite made of copper oxide (CuO) and aluminum oxide (Al2O3) with two different morphologies of copper oxide (Spherical-sCuO and Nanoplate-pCuO), which was made using the Spark Plasma Sintering (SPS) process on a titanium substrate as an orthopedic implant. Two different weight percents of copper oxide nanostructures of sCuO NP (10 wt%, 20 wt%) and pCuO NP (10 wt%, 20 wt%) have been used in this research. Synthesized nanocomposites were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscope (FESEM). Based on the obtained results, the XRD pattern and XPS confirmed that the nanocomposites were successfully synthesized without impurity. FESEM images showed that CuO nanoparticles and nanoplates were distributed on the alumina matrix homogeneously. The antibacterial activity of synthesized nanocomposites was investigated using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), gram-negative and gram-positive bacteria, respectively. Antibacterial activity results showed that CuO nanoparticles had high antibacterial activity, and the effect of CuO nanostuctures depended not only on their morphology and size, but also on the type of microorganisms. Furthermore nanocomposite with nanoplate copper oxide exhibited more bioactivity properties than the spherical shape. S. aureus showed greater resistance to CuO nanostructure, while E. coli was more susceptible to them (15%). In addition, toxicity tests showed that nanoplate copper oxide exhibited greater toxicity due to its high surface reactivity than spherical nanoparticles. This study provides new insights into the role of copper oxide nanoparticle morphology in the properties of nanocomposites for use as orthopedic implants.
Mahdi Behjati , Seyed Ali Asghar Akbari Mousavi , Yaser Vahidshad,
Volume 22, Issue 4 (12-2025)
Abstract
This work presents a comprehensive investigation of the high cycle fatigue behavior of Haynes 25 cobalt-based superalloy and its welds produced by pulsed continuous-wave (CW) laser welding. The alloy, manufactured through vacuum induction melting and electroslag remelting followed by rolling and annealing, exhibited a yield strength of 650 MPa, an ultimate tensile strength of 1050 MPa, and an outstanding elongation of 57% at room temperature. The fatigue limit was determined by test method as 200 MPa for lifetimes exceeding 10⁸ cycles, highlighting its excellent resistance to cyclic loading. For the weld zone, fabricated under optimized pulsed CW laser parameters, the yield and ultimate tensile strengths were 660 MPa and 965 MPa, respectively, with a fatigue limit of 175 MPa. Advanced microstructural analyses using OM, SEM, EBSD, and XRD revealed an austenitic FCC matrix with carbide precipitates, predominantly (W, Cr)₇C₃ and M₆C, decorating both the matrix and grain boundaries. Fatigue crack initiation in the base metal was associated with carbide clusters near the surface, while in the weld zone it was strongly linked to near-surface gas porosity defects. These findings not only establish fundamental fatigue benchmarks for Haynes 25 but also provide the first direct insights into the microstructural origins of fatigue damage in its laser-welded joints, thereby addressing a critical knowledge gap for its deployment in high-temperature and cyclic-loading environments.
Sahar Ziraki, Amir Moghaddam Kia, Ramin Ebrahimi,
Volume 22, Issue 4 (12-2025)
Abstract
In this study, an existing approach for estimating fatigue life using tensile data was extended and applied to 4340 steel under different temperature. The S-N and strain-life curves were plotted at 25, 200, and 350 ˚C. The Basquin and Coffin-Manson equation constants were determined based on the corrected true fracture stress and strain values. Moreover, the b constants were approximated as -0.065, -0.072, and -0.073 at 25, 200, and 350 ˚C, respectively. This was achieved by setting the alternating stress equal to the fatigue limit in an infinite number of cycles when b leveled off. The transition fatigue life of 1000 cycles was considered for 4340 steel to determine the c constants, which were determined to be -0.69, -0.7, and -0.699, at 25, 200, and 350 ˚C, respectively and the strain-life curves were plotted. Comparison of S-N curves obtained from both fatigue and tensile data revealed strong agreement, indicating that the tensile test is a simple and cost-effective method capable of providing a quick estimate of high- and low-cycle fatigue behavior and serving as a suitable alternative to conventional fatigue testing.
Pravin Jadhav, R.s.n Sahai,
Volume 23, Issue 1 (3-2026)
Abstract
The development of polymer composite materials for gear applications has gained significant attention due to the growing need for lightweight, corrosion-resistant, and high-performance alternatives to traditional metallic gears. This literature review consolidates key findings and insights from numerous studies, highlighting the advancements, challenges, and potential of polymer composites in gear applications. High-performance polymers such as poly ether ether ketone (PEEK), poly ether ketone(PEK), poly ether ketone ketone (PEKK) and poly aryl ether ketone (PAEK) especially when reinforced with multi-walled carbon nanotubes (MWCNTs) and functionalized MWCNTs, exhibit superior mechanical, thermal, and tribological properties. These enhancements include improved strength-to-weight ratios, wear resistance and load transfer capabilities. The review also examines the influence of various parameters on gear performance. The necessity for standardized testing methods and benchmarks to evaluate wear, surface temperature, roughness and environmental exposure is emphasized to ensure reliability and consistency. This study focuses on study of development of high performance polymer composite materials for gear applications and performance analysis of these gears.
Asiehsadat Kazemi, Maryam Hashemi, Mohammad Mohammadnezhad,
Volume 23, Issue 1 (3-2026)
Abstract
Potassium bromide (KBr) crystal structure attracts attention due to its various applications in electronic and optical devices as well as its potential in inducing local electrostatic fields. Fabricating this crystal via the conventional Czochralski method or more novel epitaxial methods is very costly. Here, with the focus on surface properties, a simple low-cost technique is employed based on the usage of KBr powder, pellet making, and pressure appliance for the fabrication of pellet crystals. These pellets have been annealed at various temperatures and studied via atomic force microscopy; morphologically and structurally. Our results demonstrate that increasing the temperature before the KBr melting point significantly reduces different roughness parameters, the height of the atomic steps, and the distance between them. At 500 °C, the atomic steps are more regular than at other temperatures, surface flatness and crystallinity are enhanced, approaching the quality of commercial single crystals. These modifications improve the quality of the crystals significantly, for various applications. Force spectroscopic measurements across atomic step edges of KBr, demonstrates higher forces with respect to flat regions. These engineered steps could serve as nanoscale templates for directing the self-assembly of molecules or for creating spatially varying electrostatic potentials in 2D material heterostructures.
Mohadeseh Karimi, Mohammad Hossein Enayati, Fatemehsadat Sayyedan,
Volume 23, Issue 1 (3-2026)
Abstract
The aim of this study was to optimize the values of current density and carbide concentration in electrodeposition process of Ni-Fe(Si-Ti)C nanocomposite coating on the AISI 304 stainless steel. The optimal current density in each electrolyte was determined using scanning electron microscope (SEM) images and energy-dispersive spectroscopy (EDS) analysis. Corrosion behavior and wear resistance of the optimized coatings were examined by TOEFL polarization test in 3.5 wt.% NaCl solution and ball-on-disk apparatus, respectively. The values of 30 mA/cm2 and 10 mA/cm2 were obtained to be the optimal current densities for electrolytes containing 6 g/L and 12-18 g/L double carbide, respectively. Electrochemical measurements declared that the corrosion rate decreased from 0.0829×10-5 mA/cm2 to 0.0208×10-5 mA/cm2 with increasing the concentration of carbide in the electrolyte from 6 g/L to 18 g/L. Moreover, the friction coefficient of the substrate was found to be significantly greater than that of the coated samples.
Zainab T Hussain, Wasna’a M Abdulridha, Murooj A Abood, Farqad Saeed,
Volume 23, Issue 1 (3-2026)
Abstract
In this study, RF magnetron sputtering was employed to create titanium dioxide (TiO2) thin films doped with zirconium oxide (ZrO2) (TZO) onto quartz and silicon substrates at 100oC for the purpose of evaluating the effect of ZrO2 doping on the microstructural, electrical, optical and gas sensing properties of the TiO2 films. Different doping concentrations (0.0, 2.0 and 4.0 wt.%) were used to compare performances of the films with a thickness ranging between 147 nm to 178 nm. Structural and surface morphology characterizations of the prepared films were carried out by X-ray diffraction (XRD) and atomic force microscopy (AFM) techniques. The surface morphology of the prepared TZO films showed a gradual reduction in the grain size while the doping concentration increased. The optical characteristics of the films also exhibited an increasing trend in the optical band gap with the rising ZrO2 concentration. TiO2 films showed an n-type conductivity as confirmed by Hall's measurement. The results of the gas sensing experiments revealed that the sensitivity of the TZO films for the detection of ethanol vapor increased with an increase in the concentration of ZrO2 dopant. Therefore, TZO film with 4.0 wt.% of ZrO2 could be used as an effective sensor for detecting ethanol vapor.
Alireza Hajialimohammadi,
Volume 23, Issue 1 (3-2026)
Abstract
This study successfully synthesized the CoCrFeNiMn high-entropy alloy (HEA) using a two-step powder metallurgy approach: mechanical alloying (MA) followed by spark plasma sintering (SPS). The research investigated the effects of processing parameters, specifically MA duration and SPS temperature, on the alloy's microstructure, densification, and mechanical properties. X-ray diffraction (XRD) analysis after 25 hours of MA (ball-to-powder ratio of 10:1) confirmed the formation of a single-phase face-centered cubic (FCC) solid solution. Scanning electron microscopy (SEM) images revealed significant powder particle refinement, with average particle sizes decreasing from initial micrometers to sub-micrometer ranges. The alloyed powders were then consolidated via SPS at temperatures of 800°C, 900°C, and 1000°C (40 MPa, 10 min in argon). Detailed analysis of the sintered samples showed relative densities ranging from 95.78% to 96.77%, with the highest density (96.77%) achieved at 1000°C. Vickers microhardness measurements exhibited a peak hardness of 446 HV at 900°C, with a decrease to 420 HV at 1000°C, primarily due to grain growth. This research establishes the combined MA and SPS approach as effective for producing high-density, high-hardness HEAs, underscoring the critical role of processing parameters in tailoring their final properties.
Muayad Raheem Hussein, Sabah Hasan Jumaah, Ali N. Majees,
Volume 23, Issue 1 (3-2026)
Abstract
In the current study, titanium dioxide (TiO₂) nanoparticles were synthesized and subsequently combined with chitosan (CS) and silver (Ag) to augment their antimicrobial effectiveness. The synthesized TiO₂, TiO₂-CS, and TiO₂-CS-Ag nanocomposites were subjected to various characterization analyses in order to thoroughly assess their structural, morphological, and compositional attributes. XRD analysis substantiated the phase transition from anatase to rutile consequent to incorporation of chitosan and silver, accompanied by a diminution in nanoparticle dimensions. FTIR spectra corroborated the existence of functional groups linked to chitosan and silver, while FESEM illustrated morphological modifications, notably the emergence of polygonal nanostructures within the TiO₂-CS-Ag composite. The antibacterial efficacy of the synthesized nanocomposites was evaluated against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Although pure TiO₂ demonstrated minimal antibacterial properties, the TiO₂-CS and TiO₂-CS-Ag composites exhibited substantial inhibition zones, with the most pronounced efficacy recorded for the TiO₂-CS-Ag composite attributable to the synergistic interaction between chitosan and silver nanoparticles. BET analysis revealed that the augmented antimicrobial activity was associated with the increased surface area of the TiO₂-CS-Ag nanocomposite.
Samira Pishkar Ahrab, Mahdiyeh Pourali, Mohammadtaghi Hamedani,
Volume 23, Issue 1 (3-2026)
Abstract
Fe3O4/ZnO/CuO nanocomposites with various molar ratios of CuO were successfully synthesized. Sol-gel method was used to syntehesize nanocomposite materials at a low temperature. A set of experiments, including X-ray diffraction (XRD), Dynamic Light Scattering (DLS), scanning electron microscopy (SEM), and UV-Vis spectroscopy, was used to confirm the successful synthesis of Fe3O4/ZnO/CuO nanocomposites in crystalline form.
The photocatalytic activity of the samples was investigated via the degradation of methylene blue (MB) dye
from synthetic wastewater under three distinct conditions: visible light, ultraviolet light, and a combination of visible light with ultrasonic treatment. Fe3O4/ZnO/CuO nanocomposite with a molar ratio of 1:1:0.5 showed the highest photocatalytic activity when irradiated with either visible or ultraviolet light. Furthermore, when visible light was combined with ultrasonic treatment, complete (100%) removal of methylene blue was achieved within 120 minutes. The results demonstrate that these nanocomposites are efficient catalysts for wastewater treatment through the removal of organic pollutants Fe3O4/ZnO/CuO nanocomposites with various molar ratios of CuO were successfully synthesized. Sol-gel method was used to syntehesize nanocomposite materials at a low temperature. A set of experiments, including X-ray diffraction (XRD), Dynamic Light Scattering (DLS), scanning electron microscopy (SEM), and UV-Vis spectroscopy, was used to confirm the successful synthesis of Fe3O4/ZnO/CuO nanocomposites in crystalline form.
The photocatalytic activity of the samples was investigated via the degradation of methylene blue (MB) dye
from synthetic wastewater under three distinct conditions: visible light, ultraviolet light, and a combination of visible light with ultrasonic treatment. Fe3O4/ZnO/CuO nanocomposite with a molar ratio of 1:1:0.5 showed the highest photocatalytic activity when irradiated with either visible or ultraviolet light. Furthermore, when visible light was combined with ultrasonic treatment, complete (100%) removal of methylene blue was achieved within 120 minutes. The results demonstrate that these nanocomposites are efficient catalysts for wastewater treatment through the removal of organic pollutants
Zahra Zalnezhad, Morteza Sasani Ghamsari, Hamid Haratizadeh,
Volume 23, Issue 1 (3-2026)
Abstract
Silicon carbide (SiC) is one of the most important silicon-based compounds, owing to its favorable physical, chemical, and biological properties, and is widely employed in various fields such as electronics, chemical industries, and quantum computing. Several methods have been reported for synthesizing SiC nanoparticles, including chemical vapor deposition (CVD), hydrothermal synthesis, carbothermal reduction, and sol–gel processing. Among these, the sol–gel method has attracted significant attention due to its high yield, process controllability, biocompatibility, accessibility of precursors, and ability to produce nanoparticles. In this study, SiC nanosized powders were synthesized through the sol–gel route combined with carbothermal reduction, using tetraethyl orthosilicate (C2H5)4SiO4) and sucrose (C11H22O11) as the silicon and carbon sources, respectively. The silica/sucrose composite was subjected to carbothermal reduction under an argon atmosphere at a pressure of 10 mTorr in a vacuum furnace at 1350°C for 3 h. The structural properties of the synthesized SiC nanopowders were analyzed using X-ray diffraction (XRD), while their optical characteristics were investigated through FTIR, diffuse reflectance spectroscopy (DRS), and photoluminescence (PL). This work demonstrates a greener, lower-temperature route to phase-controlled SiC nanoparticles with optically active vacancy centers.
Mohsen Sadeghpour Motlagh, Sara Banijamali, Bijan Eftekhari Yekta,
Volume 23, Issue 1 (3-2026)
Abstract
This study investigates the crystallization behavior and microstructural evolution of lithium metasilicate (Li₂SiO₃) glass subjected to thermal histories designed to emulate the cooling stage of zirconia infiltration in dental restorations. Three thermal routes were examined: (i) a non-isothermal schedule to identify crystallization and melting events, (ii) a controlled isothermal schedule to obtain homogeneous glass–ceramic microstructures, and (iii) a quasi-isothermal natural cooling schedule from the molten state to mimic the thermal profile during infiltration without reproducing actual capillary flow or interfacial reactions. Phase identification and quantitative analysis were performed by X-ray diffraction with Rietveld refinement, and the resulting microstructures were characterized by field-emission scanning electron microscopy. Under isothermal conditions, lithium metasilicate (Li₂SiO₃), lithium disilicate (Li₂Si₂O₅), γ-spodumene (γ-LiAlSi₂O₆), β-lithium phosphate (β-Li₃PO₄), and quartz crystallized with an overall crystallized fraction of approximately 62±0.9 wt.%. In contrast, quasi-isothermal cooling produced a crystallized fraction exceeding 87±1 wt.%, dominated by lithium metasilicate (Li₂SiO₃), β-lithium phosphate, quartz, and cristobalite, with neither lithium disilicate (Li2Si2O5) nor γ-spodumene (γ-LiAlSi₂O₆) detected under the present XRD conditions. The quasi-isothermal route also generated significantly coarser morphologies: average crystal length and thickness were roughly 10-fold and 31-fold larger, respectively, than those in the isothermally treated sample. These results demonstrate that the thermal path strongly governs phase assemblage, crystallized volume fraction, and crystal morphology in lithium silicate glass–ceramics. By clarifying how controlled versus quasi-isothermal cooling histories shape the final microstructure, this work provides a structural basis for optimizing lithium silicate glasses used in zirconia infiltration technology and for guiding future studies on the mechanical and functional performance of these materials.
Ardalan Aalipour, Azam Moosavi,
Volume 23, Issue 1 (3-2026)
Abstract
This study evaluates the mechanical performance of a metakaolin-based geopolymer matrix reinforced with quartz particles and polypropylene fibers, in comparison with a Portland cement-based matrix. Compressive strength, shrinkage, and flexural strength tests reveal that incorporating 20 wt% quartz particles significantly improves the mechanical properties of both matrices. The combined use of quartz particles and fibers contributes to shrinkage crack control and dimensional stability through synergistic effects involving particle–matrix interactions, fiber–matrix bonding, fiber surface characteristics, and toughening mechanisms. In the geopolymer matrix, the reinforcement effect of quartz particles is more pronounced due to the formation of a strong and chemically active interfacial bond. Compared with Portland cement composites, quartz particles increase the flexural and compressive strengths of geopolymer composites by approximately 2.5 and 1.3 times, respectively. The addition of 0.5 wt% polypropylene fibers slightly reduces strength but enhances energy absorption and alters the failure mode from brittle to more ductile. Overall, the results highlight the role of fibers in suppressing or arresting brittle fracture in cementitious and geopolymeric composites.
Seyed Mohammad Mirghasemi, Ehsan Mohammad Sharifi, Gholam Hossein Borhani,
Volume 23, Issue 1 (3-2026)
Abstract
The hot deformation behavior modeling and microstructural evolution of low-carbon boron steels with Ti (FBT) and Nb (FBN) additions were investigated and compared with a baseline boron-treated steel (FB) in our previous work. Hot compression tests were conducted at temperatures of 850–1150 °C and strain rates of 0.01–10 s⁻¹. Flow curve analysis revealed that both Ti and Nb increased flow stress and delayed the onset of dynamic recrystallization (DRX), with the effect more pronounced in FBN. Constitutive analysis based on the Arrhenius model showed that the activation energy of deformation increased from 293.37 kJ/mol in FB to 314.15 kJ/mol in FBT and 353.04 kJ/mol in FBN, highlighting the strong pinning effect of precipitates. Critical stresses and strains (σc, σp, εc, εp) followed the order FB < FBT < FBN, indicating higher resistance to recrystallization in the microalloyed steels. DRX kinetics, modeled using the Avrami equation, yielded exponents of 2.09, 1.65, and 1.88 for FB, FBT, and FBN, respectively, confirming that Ti suppressed nucleation more strongly than Nb. Microstructural analysis demonstrated that Ti inhibited BN formation and promoted TiN/Ti(C,N), whereas Nb retained BN and generated Nb(C,N), mainly at MnS interfaces. Grain size distribution analysis revealed that both FBT and FBN exhibited significantly finer and more homogeneous grains compared to FB, with average grain sizes at 1150 °C (0.1 s⁻¹) of 17.3 μm in FBT and 17.0 μm in FBN, nearly half that of FB (33.6 μm). Overall, Ti and Nb additions distinctly altered the high-temperature deformation and recrystallization mechanisms of boron steels, enhancing grain refinement while suppressing DRX, thereby extending the findings of our previous study on FB.
Sibbt Jabbar, Dalya Hameed, Imad Disher,
Volume 23, Issue 2 (6-2026)
Abstract
Geopolymer/nano carbon black composite is a promising electrically conductive smart material that can be used in self-heating and self-sensing applications. This paper studies the effect of adding nano carbon black to the physical, mechanical, electrical, and electrothermal performance of metakaolin-based geopolymer. Carbon black was added at the percent of 5%, 10%, 15%, and 20% by weight of metakaolin; the compressive strength was tested at various ages of 7, 14, 28, and 90 days, and the electrothermal performance was tested using AC and DC voltages. The results showed that a compromise between suitable compressive strength and high electrothermal conversion could be achieved when a specific balance between the carbon black percent and the lowest water content is established. A composite with a compressive strength of 27 MPa and stable electrothermal performance reaching 142°C at 9V DC can be prepared using 20 wt% of carbon black and a water-to-metakaolin ratio of 0.549, which is used as a smart material in construction applications.
Moges Tsega Yihunie,
Volume 23, Issue 2 (6-2026)
Abstract
Copper oxide (CuO) nanoparticles (NPs) were synthesized by the sol-gel method, followed by calcination at 600 oC for 2 h. The XRD pattern indicated that the synthesized CuO NPs had a monoclinic structure, with an average crystallite size of 53 nm. The FT-IR spectra showed that surfactant molecules were adsorbed on the surface of the CuO nanoparticles, along with the presence of Cu-O bonding. The TEM analysis revealed rod-like CuO NPs with diameters of about 50 nm and lengths ranging from 150 to 200 nm. The XPS analysis confirmed that copper and oxygen were synthesized as the main components with Cu2+ and O2-oxidation states. The optical band gap of CuO was calculated to be 3.5 eV. The maximum PL emission was recorded at 430 nm for the 365 nm excitation wavelength, and the change in PL intensity and peak shift was calculated as a function of excitation wavelength. The Mie analysis results also showed that when crystallite sizes increased, so did the maximum values of extinction efficiency, scattering efficiency, asymmetry, and scattering matrix. The findings of this study imply that CuO NPs could be a viable choice for a variety of luminous device applications.
Ehsan Bazzaz, Majid Alitavoli, Mehdi Yarmohammad Tooski, Mohammad Mehdi Bazzaz,
Volume 23, Issue 2 (6-2026)
Abstract
Improvement of the mechanical properties of the coated surfaces was the matter of significant researches for a long time. A lot of physical and chemical operations were applied and examined on the coating surfaces successfully, but the effect of the mechanical treatments was not widely investigated. In this paper, the effect of a surface mechanical treatment on the micro coating layer has been studied and investigated. For this purpose, the necessary conditions have been created for implying impact to the coating surface. A setup of gas gun facility with well-designed and prepared projectiles are used to strike the sample surface with different speeds. A significant number of impacts have been inflicted on the test sample of the spade drill insert cutting tool. The consequence of this process is the change in crystal structure of the coating layer, which shows that under the created conditions, the crystal structure was not destroyed and instead getting compacted so that the size of the crystal grains has been reduced and considerably refined. Subsequent studies using electron microscopy have led to the measurement of the average size of the crystalline grains before and after impacts. Obviously, a significant effect has been observed and a meaningful trend has been seen for this change in the form of a linear relationship. The main result is that about 4% reduction in the average grain size happens when the impact speed changes by 10m/s. In this way, the principal basis for the use of this surface treatment in improving the surface properties of the micro coating layers is provided. This leads to the application of such treatments as an industry process for improvement of thin coating mechanical properties.
Daniela Grigorova, Gyunver Hodjaoglu, Feyzim Hodzhaoglu,
Volume 23, Issue 2 (6-2026)
Abstract
Producing high-purity iron powders with controlled particle morphology is essential for advanced powder metallurgy, additive manufacturing, and functional materials. However, achieving precise morphological control in environmentally benign, additive-free electrolytes remains challenging. This study systematically investigates the galvanostatic electrodeposition of iron powder from sulfate-based electrolytes containing 10.0 and 50.0 g·L⁻¹ Fe²⁺, focusing on the interplay between current density, pH evolution, deposition efficiency, and particle structure. A clear transition from compact, adherent deposits at low current densities to dendritic, easily detachable powders at higher values was observed. SEM analysis revealed well-defined dendritic aggregates at 7 A·dm⁻² (30–80 μm), whereas highly fragmented, porous agglomerates formed at 10 A·dm⁻², accompanied by fine-scale fragmentation driven by intense hydrogen evolution. XRD confirmed pure α-Fe for current densities up to 7 A·dm⁻², while partial oxidation to Fe₃O₄ occurred at 10 A·dm⁻²; EDX mapping further supported this surface oxidation. The deposited mass increased linearly with current density for both Fe²⁺ concentrations, with regression models yielding R² values above 0.96. Current efficiency decreased at high current densities due to enhanced parasitic reactions. Overall, the results demonstrate that galvanostatic electrodeposition in additive-free sulfate media enables controlled synthesis of iron powders, with tunable morphology and phase purity governed primarily by current density and electrolyte composition.
Sumrit Mopoung, Rinlaphat Thanakulwaranon,
Volume 23, Issue 2 (6-2026)
Abstract
Activated charcoals were prepared by activation with 600 W microwave irradiation in combination with pretreatments of tamarind wood derived charcoal in boiling mixtures with NaOH (1 g : 0 g - 1 g: 0.12 g). The samples were characterized by FTIR, XRD, SEM-EDS, and BET, and used for catalytic nitrite c oxidation under air atmosphere in the absence of light at 30°C, pH 6.5, and 120 rpm shanking for improved efficiency. The results show that the percent yields of tamarind wood derived activated charcoals (ACCs) were 88.51% - 94.66 %. The main carbonate compounds of ACCs are present in the materials after activation. Na+ ions and water molecules could be inserted into the graphitic layers during pretreatment and efficiently effected surface cracking of ACCs by 600 W microwave irradiation. The surface cracklings and porosities of ACCs increased with increasing concentration of NaOH from 1 M to 3 M with optimum at 2 M NaOH. The final products are mesopore materials containing macro and meso hole channels. It was found that the nitrite conversions exhibit high reaction rates and are completed within 20 min. The reactions proceed via catalytic oxidations and their rates increase with increasing concentrations of NaOH activation, while nitrite conversions via the disproportionation reaction were inhibited.
