نشریه علم و مهندسی سرامیک
سال دهم شماره 1 (پیاپی 36، بهار 1400)

In this research, with use of copper chloride, indium chloride, Thiourea (source of sulfur) and deionized  water as solvent, using hydrothermal method at 180 ° C and at time of 4, 6, 8, 12, 14, 16, 18 and 20 hours, the composition of CuInS2 nanoparticles was synthesized by Stoichiometric ratio of (1: 1: 2), and in the next step, this compound (CuInS2 ( with cobalt additive at 180 ° C and at time of 20 h with Stoichiometric composition of the CuIn1-xCoxS2 ​​(X = 0.1 , x=0.2)  was synthesized and the Structural changes, microstructural and Optical properties have also been studied. The use of X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and Diffuse Reflection Spectroscopy (DRS) were investigated for the optical and microstructural properties. The results show that crystallite size of the synthesized single-phase nanoparticles of CIS at 16, 18 and 20 hours are 26, 29 and 32 nm, respectively. With the use of the diffraction Peaks of the planes such as (112), (220) and (312) for the sample synthesized in 20 hours, the lattice constant value a is 5.52 Å and c is 11.11 Å. FESEM micrographs showed irregular polyhedral shape for particles presence in sample synthesized in 18 hours and flaky shape for particles presence in sample synthesized in 20 hours. The band gap for a single-phase synthesized sample at 20 hours is 1. 54 eV. The band gap of (CuIn1-xCoxS2) with values (X = 0.1) was calculated to be 1.92 eV.

Given the growing importance of photocatalysts in the industrial wastewater treatment, in this study, TiO2-CuO (TC) composite nanoparticles were synthesized by sol-gel method. Tetrabutyl orthotitanate (TBT), copper nitrate-3hydrate and ethanol were used as titanium dioxide precursor, copper oxide precursor and solvent, respectively. The structural, optical, photocatalytic activity and BET-BJH properties of nanoparticles were studied by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), UV-Vis absorption spectroscopy and Brunauer-Emmett-Teller specific surface area (BET). The results of XRD and BET analysis show that the TiO2-CuO composite reduced the crystallite size and increased the specific surface area. Also the results of XRD, EDX, and MAP analysis confirmed the presence of TiO2, CuO in the nanocomposite. The specific surface area for the pure mesoporous titania (T) and TiO2-CuO (TC) nanocomposite samples are 60.25 282 m2/g and 163.22 m2/g, respectively. Absorption edge (λedg) and band gap energy (Eg) of T and TC samples are 365.7 nm, 3.39 eV and 375 nm and 3.30 eV, respectively. The results of FESEM showed that the particles were somewhat agglomerated and the particle size of the composite sample was 10-15 nm.

Nickel-phosphorus coatings (Ni-P) are widely used in industry due to their high hardness, corrosion resistance and very good mechanical and chemical properties. Oxide particles such as TiO2 can be used to increase the wear resistance of these coatings. In this study, the Ni-P-W-TiO2 composite coating was deposited on the AISI 304L steel substrate using the electroplating method. Electroplating was performed at concentrations of 10, 20, and 30 g/L TiO2, and the effect of TiO2 concentrations on the microstructure, corrosion behavior, and wear behavior was investigated. Coatings were characterized by scanning electron microscopy (SEM). In order to investigate corrosion resistance, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests were used in 3.5% NaCl aqueous solution. A pin on disk test was used to test the wear resistance of uncoated and coated samples. Sample micro-hardness was also measured by the Vickers hardness test. Examination of the microstructure showed that the best TiO2 concentration for deposition was 20 g/L. The results of Tafel and electrochemical impedance spectroscopy tests were also consistent with microscopic images, and the results showed that the coating formed at concentration of 20 g/L had the highest corrosion resistance compared to other coated and non-coated samples. Also, the results of the wear test showed that increasing the TiO2 concentration increases the micro-hardness and wear resistance.

In the present study, zinc oxide nanoparticles in three different forms (spherical, rod and sheet) were synthesized by a hydrothermal method. The obtained products were characterized by X-ray diffraction (XRD), filed emission scanning electron microscopy (FESEM), EDX elemental analysis and UV-Vis spectroscopy. The photocatalytic properties were investigated using congo red (CR) degradation under ultraviolet iradiation . ZnO nanorods exhibited higher photocatalytic activity as compared to other morphologies (sheet and spherical) that occurred with a 97% destruction rate within two hours at pH = 8. The energy gap of the synthesized nanoparticles was calculated by tauc method and the relationship between the obtained values ​​and the photocatalytic activity of the particles was investigated. It was found that, the efficiency of the photacatalytic reaction is more dependent on the particle size and morphology than on the band gap. The kinetics results showed the first-order reaction mechanism for the photocatalytic activities of the nanoparticles.

The ZnO films and ZnO films doped with Al were deposited on glass substrates by radio frequency magnetron sputtering at room temperature. Films were annealed in an electrical furnace with Ar atmosphere at three different temperatures 400, 500, and 600 oC. The values of optical density of ZnO films were greater than respect to ZnO films doped with Al. With increasing annealing temperature, the lateral size values of nanoparticles for ZnO films were increased. The ZnO films annealed at 400 ⁰C have minimum value of the nanoparticles lateral size in about of 22.59 nm.  The ZnO films doped with Al and annealed at 600 ⁰C have maximum value of the nanoparticles lateral size in about of 22.59 nm.  Changes in the height of the scanned surface of the layers indicated that the zinc oxide film has a sharp jump of 25nm at room temperature. Also, the ZnO films doped with aluminum at 600 °C have less ups and downs than other temperatures and the height is around 6 nm. With increasing the annealing temperature, the fractal dimensions’ values of the zinc oxide films were decreased.

In this research oxyacetylene ablation behavior of SiC/ZrB2 multilayer coating prepared on graphite by infiltration and plasma spray method was investigated. SiC inner layer was prepared on graphite substrate by infiltration method in Si, C and Al2O3 powder bed at 1600°C under argon atmosphere. Microstructural characterization confirmed the formation of SiC graded coating with average thickness of 600μm. ZrB2 outer layer coating was prepared on SiC coated graphite via shrouded plasma spray. Microstructural characterization of ZrB2 outer layer showed that the mechanical bonding is created at the coating-substrate interface without any crack and discontinuity. The results of oxyacetylene ablation test revealed the good ablation resistance of SiC/ZrB2 coated graphite. Mass ablation rate for coated sample was 0.0393 × 10-3 g.cm-2.s-1. This is attributed to the formation of ZrO2-SiO2 protective film on the surface.

In this research, first of all, two samples of glasses of 40SiO2–28.6B2O3–24.5Fe2O3– 6.4Na2O–0.5Cr2O3 (mol%) (chr('39')Achr('39') sample) and 36SiO2–10.3B2O3–17Fe2O3–36Na2O–0.7Cr2O3 (mol%) (chr('39')Bchr('39') sample) were synthesized using melting furnace method. Structural and magnetic properties of the samples have been studied by the X-ray diffraction (XRD) and the vibrating sample magnetometer (VSM) respectively. X-ray diffraction pattern of the chr('39')Achr('39') sample showed formation of magnetite phase and for the chr('39')Bchr('39') sample showed amorphous phase. VSM showed ferrimagnetic properties for the chr('39')Achr('39') sample, and superparamagnetic properties for the chr('39')Bchr('39') sample. Crystallization temperature of the chr('39')Bchr('39') sample obtained at 720°C using the differential thermal analysis (DTA) This glass sample heat treated at 720 °C and 860 °C for one hour in air atmosphere and they called chr('39')B1chr('39') and chr('39')B2chr('39') respectively. The XRD pattern of the chr('39')B1chr('39') sample showed formation of maghemite and hematite phase. Magnetic hysteresis loop showed saturation magnetization (Ms) about 13.5 emu g-1 for the chr('39')B1chr('39') sample. For the chr('39')B2chr('39') sample, formation of hematite phase and Fe21.34O32 was observed using XRD data. The remanence magnetization (Mr) obtained about 0.03 emu g-1 for the chr('39')B2chr('39') sample. Fourier transform infrared spectroscopy (FTIR) showed absorption peaks of Fe-O link in 571 cm-1 and 435 cm-1 for the chr('39')B1chr('39') sample and 510 cm-1 and 461 cm-1 for the chr('39')B2chr('39') sample.

Graphene, as the first presented two-dimensional material, is undergoing a growing trend in various industries. In this study, some effective parameters on the structural and microstructural properties of graphene synthesized by wet milling, in the presence of N-methyl-2-pyrrolidone (NMP) as a solvent were investigated. These variable parameters consist of the amount of graphite, solids to solvent ratio, weight ratio of pellets to solids, and the time of milling. The results of field emission scanning electron microscopy (FESEM), Raman spectroscopy and Fourier-transform infrared spectroscopy (FT-IR) analysis showed that the optimal parameters are 25 for the weight of pellets to graphite, concentration of 20 g/ml of graphite in NMP, and milling time of 6 hours. However, the application of a mixture of melamine and urea was evaluated for the exfoliation and functionalization of graphene by the planetary mill, according to the results, this mixture, showed a promising result as a promising composition for the simultaneous exfoliation and functionalization of graphene.