touraj ebadzadeh

Microwave sintering has emerged as a promising technique for the fabrication of Ti-based alloys, offering unique advantages over conventional sintering methods. The selective and volumetric heating capabilities of microwaves can result in rapid densification, microstructural refinement, and enhanced properties in Ti-Cu alloy systems. Therefore, this study aimed to synthesize an intermetallic alloy of Ti-50 at. % Cu through high-energy mechanical milling and a microwave-assisted sintering method. The objective was to expedite the sintering process of the Ti-Cu alloy using microwave assistance and analyze how this method influences the phases formed and the properties of the alloy. A Ti-50 at. % Cu powder mixture was milled for 30 hours under an argon atmosphere, then uniaxially compacted to form green samples, which were subsequently sintered by microwave heating. This method allowed for rapid consolidation without significant grain growth within a short sintering period. The effects of the sintering method and temperature on microstructure and mechanical properties were studied. The density of the sintered samples increased with rising temperatures, with the highest density of 6.54 g/cm³ obtained at 900°C. Microstructural examination revealed that the Ti3Cu4 and TiCu phases primarily formed, with an average grain size of approximately 28 nm. A high micro-hardness of ~880 HV was achieved for the dense alloy prepared using this method.

In this study, hematite nanoparticles and hematite nanoparticles doped with Ti, Sn doped have been synthesized and deposited on FTO glass for photo anode application. To make a thin layer of hematite by hydrothermal method, ammonia and ferric chloride solution react indirectly at 120 ̊C for 24 h for better adhesion of synthesized iron hydroxide on FTO glass. The   synthesized samples were calcined at 550o C. XRD analysis was confirmed that FeOOH-coated were subsequently converted to the rhombohedral structure of the a-Fe2O3.  A complete synthesis study was performed using FTIR analysis and using UV-Vis results, the bandgap energy of the samples was calculated with and without the additive. The finite structure and morphology of synthesized powders were also compared with FESEM images. The results showed that the addition of 1% wt of titanium caused the synthesis of uniform spherical nanoparticles leads to alow electrons bandgap energy of 1.85 eV.

In the present study thermal shock behavior of monolothic alumina and two types of micro and nano aluminum tianate composites have been studied using quench-strength method. The powders were wet mixed and the slurry dried. Then the grinded powders were formed by isostatic pressing. The composites were prepared by in-situ reaction sintering of alumina with nano and micronized TiO2 addition to formation of 20 wt.% aluminum titanate as secondary phase. Investigations were carried out by s-DT curves, X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) analysis. The results revealed fully formation of Al2TiO5 phases in the both case of micro and nano titania as a result of Al2O3 and TiO2 reaction sintering. The nano layer structure of the Al2TiO5 was formed at the triple junction of the alumina grains. Also thermal shock values of the alumina, micro and nano composites were measured about 230, 265 and 290 °C, respectively. Thermal shock increment of the composite in the comparison of the alumina can be related to the secondary phase effect on the rising toughness curve (R-curve) and microcracking of the composites.

Abstract Li-Ion and Ni-MH batteries are the best candidate for Electric Vehicles. Despite higher energy densities of Li-Ion batteries, because of economical reason Ni-MH Batteries are still attractive for scientist. In this investigation Cerium rich MmNi3.55Co0.75Mn0.4Al0.3 has been produced via Vacuum Arc Remelting Process. Phase characterization has shown that the predominant crystallographic phase is Hexagonal type with AB5 chemical formulation. Volumetric Sievert test has shown that the alloy could store 1%wt percent hydrogen at room temperature. Electrochemical analysis with Evium-Stat has shown that the energy density which the alloy can reversibly deliver is about 150 mAh/g.

Having sufficient and accurate understanding about kinetics of phenomena, could be an important reason for further technological progresses. Finding a white-box mathematical model for weight vs. time curves of Electrophoretic Deposition (EPD) using large and small signal analysis has been studied thoroughly in the present investigation. Weight-Time curves of nano-Mullite suspension have been trained using Simulink modeling tool. Results of the investigation illustrate that, the frequency of particles i.e. the probability of particles for collision to another ones, is decreased due to reduction of the concentration of particles in suspension. When the solid load becomes higher close to the electrode surface, the mobility of individual particle will be restricted and a collective pressure onto the particles closer to the electrode surface is supposed to develop. The accumulated particles will be forced to flocculate and form a solid packing structure. According to results of modeling, times before flocculation is suitable for deposition of highly dense coating.

Dielectric ceramics have been greatly intended owing to their composition diversity and meeting the requirements of electronic industry and wireless communication. Among these ceramics, ceramic composites composed of a dielectric ceramic phase and a sintering aid glassy phase which offer dielectric features in the microwave frequency, have been utilized for application in the LTCC (low temperature co-fired ceramics) modules. The present work has been aimed to fabricate dielectric composites of mullite microparticles- ZBS (ZnO-B2O3-SiO2) glass for use as dielectric substrates in the LTCC technology. In this regard, composites with various volume ratios of mullite and ZBS glass were fabricated. Considering the sinterability evaluation at 950°C, composite of 50 mullite-50 glass (Vol. %) was chosen as the optimized sintered composite and focused for further examinations. Monitoring thermal behavior of the optimized composite during sintering by means of X-ray diffratometry and differential thermal analysis revealed that mullite reacts with glassy phase at about 880 ºC; results in the formation of gahnite (ZnO.Al2O3) phase. Microstructural observation confirmed prismatic morphology of the gahnite crystals dispersed homogeneously in the glass matrix. Dielectric characterization utilizing network analyzer showed the resonance of the optimized composite in the microwave frequency range. Dielectric permittivity (4.5) and quality factor (4704GHz) of the optimized composite is in accordance with the requirements of the targeted technology

Raspberry-like ZnS nanoparticles were synthesized by hydrothermal method.ZnS particle size varies by controlling the amount of comb polycarboxylic acidsurfactant and polystyrene (PS) template. The products were characterized byX-ray diffraction (XRD), scanning and transmission electron microscopy, and Fouriertransformed infrared spectroscopy. Optical properties were investigated via UV-vis andphotoluminescence spectrophotometry. All samples consisted of ZnS cubic phase(sphalerite). The XRD patterns showed that surfactant has a vital effect on crystallitesize reduction. In contrast, PS template enhanced the growth rate of ZnS nanoparticles.Studies on morphology and particle size showed that increasing the amountof surfactant content causes the ZnS particle size to decrease to nanometric range.Although particle size increased by deposition of ZnS nanoparticles on the surface ofPS template, the uniformity of the particles increased considerably. A narrow range ofparticle size distribution (110-150 nm) was shown in the sample synthesized in thepresence of both surfactant (2.2 g/L) and PS template (1 cc of 2.7% w/v). The blueshift of absorption edge in UV-vis spectra with an increase in surfactant contentdemonstrated the quantum confinement effect of ZnS nanoparticles. The obtained ZnSnanoparticles displayed blue emission peaks at 400 and 425 nm. Furthermore, aschematic model is proposed illustrating ZnS formation on the surface of PS templatein the presence of the anionic surfactant.