فهرست مطالب

Advanced Ceramics Progress - Volume:6 Issue: 1, 2020
  • Volume:6 Issue: 1, 2020
  • تاریخ انتشار: 1399/02/16
  • تعداد عناوین: 6
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  • B. Shahbahrami, S. M. Rabiee *, R. Shidpoor Pages 1-15

    Cobalt ferrite nanoparticles (CoFe2O4) are well known for some distinctive characteristics such as high magnetic permeability and coercive force, good saturation magnetization, excellent physical, and chemical stability, which make them so attractive for magnetic storage, magnetic resonance imaging (MRI), drug delivery, optical-magnetic equipment, radar absorbing materials (RAM), and magnetic hyperthermia applications. According to these particularities, cobalt ferrite-based core-shell nanoparticles have been reviewed focusing on hyperthermia applications. Promoting anisotropic constant and magnetic permeability, increasing the chemical and physical stability of nanoparticles, the proper distribution of particles in aquatic environments to prevent agglomeration, sedimentation, and obstruction in a specific position, as well as enhancing biocompatibility and avoiding the disadvantages, are essential for better efficiency in hyperthermia aspect. For this purpose, the synthesis of magnetic nanoparticles of cobalt ferrite with preferentially smaller sizes, as well as a narrower range of particle size distribution, is the primary objective of the synthesis process. Hence, it is important to identify the influence of effective parameters on the size and shape of nanoparticles, the substitution mechanisms of rare-earth elements, and changing the structure and behavior of the magnetic properties by these elements and finally, the thermal properties. Moreover, surface modifications and coating are other significant parameters in hyperthermia field that are investigated to achieve a suitable and stable distribution in aqueous media, and how they behave against the magnetic field.

    Keywords: Hyperthermia, Cobalt ferrite, Rare-earth Elements, Surface modification
  • L. Farahinia, M. Rezvani *, M. Rezazadeh Pages 16-21
    Nowadays, oxyfluoride glasses have received much attention from photonic researchers as they benefit from the advantages of both oxide and fluoride glasses (low phonon energy in parallel with high mechanical and chemical durability). The purppose of this paper was to study the different glass compositions in SiO2-Al2O3-K2O-BaF2 system and investigate the BaF2 effects on their crystallization behavior and structure. Therefore, various chemical compositions with different amounts of BaF2 (20, 30, and 40mol%) were chosen and melted in alumina crucibles at 1450˚C. The sample could not melt with the lowest percentage of BaF2. On the other hand, the glass composition containing the highest amount of BaF2 was not able to show high transparency due to the phase separation that occurred in it. Finally, the sample with a 30mole ratio of BaF2 was chosen as the optimized sample due to the favorable transparency. XRD patterns showed that the samples were amorphous and it somehow proved the low transparency in the presence of higher amounts of BaF2 arose from phase separation than the unwanted crystallization. According to the DTA results, the crystallization peak of the fluoride phase decreased from 693˚C to 678˚C by increasing the content of BaF2. FT-IR spectra approved the oxyfluoride structure of the glasses. Higher BaF2 content increased the absorption of peaks in FT-IR spectra since it results in a more discontinuous structure. Fluorine loss was higher for the glass containing the highest amount of BaF2 due to the lower amount of Al2O3 in its composition.
    Keywords: Optical Glass, Oxyfluoride, Barium Fluoride
  • T. Ameri Ekhtiarabadi, M. Zandrahimi *, H. Ebrahimifar Pages 22-29
    Metallic composite coatings with ceramic particles can be used to improve the mechanical and corrosion properties of steel. In the present research, Ni-ZrO2-TiO2 composite coating was fabricated on AISI 430 stainless steel through the electrodeposition method. The effect of the current density of electroplating (15, 17, 20, and 23 mA.cm-2)was investigated on the microstructure and mechanical behavior of coated steel. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to study the morphology and phases. Micro-hardness was measured by the Wickers method, and wear behavior was evaluated by the pin-on-disk test. The results showed that the deposition of TiO2 and ZrO2 ceramic particles in the composite coating increased and then decreased by increasing the applied current density up to 20 mA.cm-2. Similar trends were observed for the variations in hardness and wear resistance of the composite coating. According to the results, the use of Ni-ZrO2-TiO2 composite coating on AISI 430 stainless steel improved the mechanical properties.
    Keywords: composite coating, TiO2, ZrO2, Current Density, Abrasive Resistance
  • M. Afzalitabar, M. Alaei * Pages 30-35
    In this research, two carbon structures silica nanohybrids Pickering emulsions were prepared. Graphite and activated carbon were carbon allotropes with different morphologies of laminar and spherical, respectively. The effect of carbon morphology investigated on the related silica nanohybrids Pickeringemulsions for C-EOR. Therefore, nanohybrids were prepared with graphite and activated carbon through the sol-gel method based on different weight percents and two different methods. X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), and Thermal Gravimetric Analysis (TGA) used characterize the synthesized samples. Pickering emulsions of these nanohybrids were prepared by utilizing octane as oil model, suitable anionic surfactants and an alcoholic co-surfactant with pH=7 at room temperature using distilled water. The apparent stability of Pickering emulsion studied over a period of one month. The results of analyses indicated that graphite/silica nanohybrids Pickering emulsions had superior properties for C-EOR in comparison to activated carbon/silica nanohybrids Pickeringemulsions. It concluded that laminar morphology is more significant than the spherical morphology of carbon structure for the mentioned purpose. According to emulsion phase morphology, the optical microscopic images showed that the best samples were 70% graphite/silica (method 2) and 50% activated carbon/silica (method 2). The results of contact angle measurement represented that the 70% graphite/silica nanohybrid (method 2) is more effective on the stone reservoir improvement, which can change the wettability from oil-wet to water-wet. Nanofluid of 70% graphite/silica nanohybrid (method 2) could reduce interfacial tension.
    Keywords: Pickering emulsion, Nanohybrid, Graphite, Activated carbon, Silica, Chemical Enhanced Oil Recovery (C-EOR)
  • F. Soleimani *, M. Rezvani Pages 36-42
    Microporous Calcium Titanium Phosphate glass-ceramics have many uses in high-tech industries. For example, they have applications in catalysts industry. In this study, different molar percentages of alumina were added to a glass with P2O5 30, CaO 45, TiO2 25 (mol%) composition. The samples were melted at 1350°C and crystallization heat treatment was performed on the glasses after cooling to make glass-ceramics. The Differential Thermal Analysis (DTA) was used to determine nucleation and crystallization temperature. The DTA curve of the sample had 4 molar% and alumina had the sharpest crystallization peak. The CP and CTP phases were the most crystalline phases in all samples. The soluble CP phase disappeared and the porous structure of the CPT crystals remained through the acid washing of the samples. The results showed that the addition of alumina decreased the crystallization temperature, time and temperature of crystallization, and also increased the average size of porosities (from 12 to 16 nm).
    Keywords: Phosphate Glass-ceramics, Nanoporous, Crystallization, Alumina
  • A. M. Fathi Dehkharghani, M. R. Rahimipour, M. Zakeri * Pages 43-48
    Lanthanum (La) doped Ceria (CeO2) has attracted considerable interest as a candidate material for thermal barrier coating (TBC) because of its low thermal conductivity and potential capability to be operated above 1250°C. In this study, La2Ce2O7 powder was synthesized through the ball mill method. The crystal structure of La3+ substituted CeO2 solid solution was investigated by X-ray diffraction in LaxCe1-xO2-x/2 (0<x< 0.5). The fluorite structure of CeO2 did not change although La3+ was the largest trivalent rare-earth ion. The lattice parameter changed from 5.41 to 5.59Å by increasing La content. Changes in the lattice parameters of LaxCe1-xO2-x/2 that were compared with the theoretical values measured by XRD were obtained based on the oxygen vacancy model. The theoretical lattice parameters were larger than the lattice parameters calculated from the X-ray diffraction pattern. Moreover, the Williamson–Hall equation was used to measure the crystallite size and strain in the LaxCe1-xO2-x/2 lattice as a function of the lanthanum content. The results showed that the presence of lanthanum in the structure reduced the crystallite size.
    Keywords: La2Ce2O7, Solid state, Synthesize, crystal structure, lattice parameters