Browsing by Author "Arianpour F."

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Characterization and Properties of Sodium Hexa-Fluorosilicate and its Potential Application in the Production of Sodium Fluoride
(2021-12-01) Arianpour F.; Arianpour A.Ç.; Aali B.
Sodium hexa-fluorosilicate (Na2SiF6) is a synthetic inorganic material with distinguished chemical, thermal and optical properties. In this research, a pure sodium hexa-fluorosilicate sample was systematically investigated via various characterization techniques. The amounts of constitutional elements and impurities were investigated using X-ray fluorescence and the chemical purity was determined as 99.89 wt%. Physical properties were calculated as 2.7085 g/cm3 for density, 0.98 m2/g for specific surface area and a mean particle size (D50) of 77.3 μm. Thermal analysis was applied to understand the degradation of Na2SiF6 till 900 °C. The mineral composition and morphology was studied using X-ray diffraction, scanning and transmission electron microscopy and revealed the existence of P321 type hexagonal structure associated by elongated prism shaped precipitated crystals. Spectroscopy studies were performed via different techniques at different ranges of measurement. Thermal stability was investigated by post-mortem phase analysis of heat treated Na2SiF6 samples and showed a well stability till 400 °C. It is proposed that the thermal dissociation of Na2SiF6 can be utilized as a facile, inexpensive and green way for the synthesis of sodium fluoride instead of routine hydrofluoric acid-based methods. The obtained results suggested that the examined sodium hexa-fluorosilicate material could potentially be used as a reliable precursor in the synthesis of fluoride and silicon based materials due to its acceptable physical properties, chemical purity and thermal behavior.
Characterization, technological properties, and ceramic applications of Kastamonu alluvial clays (Northern Turkey) in building materials
(2022-11-21) Arianpour A.Ç.; Arianpour F.
This research investigates two unexploited Pınarbaşı (PC) and Küçüksu (KC) alluvial clays from Kastamonu province in the Black Sea region (Northern Turkey) and studies their potential applications in building materials. We have characterized the samples regarding their chemical and physical properties, spectrometry, thermal behavior, phase, and microstructure. This study also explores the technological features of heated clays at 900–1100 °C (such as ceramic properties and color), dilatometry, phase, and microstructural analyses. The results show that both clays contain quartz, kaolinite, illite, and calcite as dominant phases and some clayey minerals as minors. The chemical analysis indicates that the deposits are siliceous clays with the principal oxides of SiO2 (48.43–51.58 wt%), Al2O3 (17.92–20.87 wt%), and Fe2O3 (5.93–6.91 wt%). The KC clay shows a notably high surface area of 88.51 m2/g after N2-physisorption analysis. The characterization of heated clays demonstrates that the densification occurs by forming mullite and anorthite, which are responsible for the increased mechanical strength (24.84–32.85 MPa) above 1000 °C. The overall results reveal that both clays possess suitable technological characteristics, making them favorable low-cost sustainable raw materials in producing red-fired construction and building parts. Study shows that these reserves are typical representatives of other distributed natural clay resources in the area, which generally contain high iron or high carbonate substances. It is formidable that this work is helpful to cover a part of insufficient investigations on the clayey deposits of the Black Sea region.
Effects of chelating agents on the sol-gel synthesis of nano-zirconia: Comparison of the Pechini and sugar-based methods
(2020-05-01) Kazemi F.; Arianpour F.; Taheri M.; Saberi A.; Rezaie H.R.
This study focused on the comparison of the Pechini and sugar-based combustion synthesis methods to produce nano-zirconia. Zirconium hydroxide was utilized as metal precursor and citric acid, sucrose, and fructose were used as chelating agents, followed by calcination at 500, 600, and 700°C in air, respectively. Characterization was conducted by thermal analysis, specific surface area measurement, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning and transmission electron microscopy. When sucrose and citric acid were used as chelating agents during synthesis, mixtures of monoclinic and tetragonal phases were formed after calcination at 600 and 700°C. In the fructose samples, the tetragonal structure was the unique characterized phase. The tetragonal parameters in the fructose samples were determined using the diffraction data and the lattice parameter ratio was proven to increase with the temperature increase. Compared with the citrate and sucrose samples, the largest specific surface area (27 m2·g−1) and smallest particle size (39.1 nm) were obtained for the fructose sample after calcination at 700°C. The study revealed the formation of single-phase stabilized tetragonal zirconia using fructose as chelating agent after calcination at 500°C, and the presence and formation mechanism of stabilized tetragonal phase were also discussed on the basis of the X-ray and electron diffraction studies.
Incorporation of Nanoalumina Improves Mechanical Properties and Osteogenesis of Hydroxyapatite Bioceramics
(2018-04-09) Tavassoli H.; Javadpour J.; Taheri M.; Mehrjou M.; Koushki N.; Arianpour F.; Majidi M.; Izadi-Mobarakeh J.; Negahdari B.; Chan P.; Ebrahimi Warkiani M.; Bonakdar S.
A handful of work focused on improving the intrinsic low mechanical properties of hydroxyapatite (HA) by various reinforcing agents. However, the big challenge regarding improving mechanical properties is maintaining bioactivity. To address this issue, we report fabrication of apatite-based composites by incorporation of alumina nanoparticles (n-Al2O3). Although numerous studies have used micron or submicron alumina for reinforcing hydroxyapatite, only few reports are available about the use of n-Al2O3. In this study, spark plasma sintering (SPS) method was utilized to develop HA-nAl2O3 dense bodies. Compared to the conventional sintering, decomposition of HA and formation of calcium aluminates phases are restricted using SPS. Moreover, n-Al2O3 acts as a bioactive agent while its conventional form is an inert bioceramics. The addition of n-Al2O3 resulted in 40% improvement in hardness along with a 110% increase in fracture toughness, while attaining nearly full dense bodies. The in vitro characterization of nanocomposite demonstrated improved bone-specific cell function markers as evidenced by cell attachment and proliferation, alkaline phosphatase activity, calcium and collagen detection and nitric oxide production. Specifically, gene expression analysis demonstrated that introduction of n-Al2O3 in HA matrix resulted in accelerated osteogenic differentiation of osteoblast and mesenchymal stem cells, as expression of Runx-2 and OSP showed 2.5 and 19.6 fold increase after 2 weeks (p < 0.05). Moreover, protein adsorption analysis showed enhanced adsorption of plasma proteins to HA-nAl2O3 sample compared to HA. These findings suggest that HA-nAl2O3 could be a prospective candidate for orthopedic applications due to its improved mechanical and osteogenic properties.
Kinetic study of carbothermal reduction of zirconia under vacuum condition
(2020-01-01) Kazemi F.; Arianpour F.; Rezaie H.R.
In this research, formation mechanism and kinetics of vacuum carbothermal synthesis of zirconium carbide using zirconium acetate and sucrose are discussed. The study of non-isothermal reduction was conducted by thermogravimetry analysis and heating the samples in argon and vacuum conditions up to 1773 K, and then the heat exchange values of reactions were calculated. Isothermal formation mechanism of carbide phase was investigated by heating the samples at 1473 K and 1673 K in argon and vacuum atmospheres followed by X-ray diffraction and quantitative phase analysis. Results showed that in non-isothermal state, the carbothermal reduction of zirconia is a heterogeneous reaction with multiple steps. For isothermal reaction, the kinetic parameters such as activation energy and pre-exponential factor were calculated as 70.56 kJ mol−1 and 11.22 × 10−2 S−1, respectively. It was presented that the activation energy value extracted from isothermal reaction is completely in accordance with the final step of non-isothermal results.
Thermodynamic study of zirconium carbide synthesis via a low-temperature pyrovacuum method
(2020-09-01) Arianpour F.; Kazemi F.; Rezaie H.R.
In this research, the thermodynamic aspect of the nano-sized zirconium carbide production is investigated via a facile, low-temperature and cost-effective carbothermal method under vacuum and argon atmospheres. The starting materials were zirconium acetate and sucrose as zirconium and carbon precursors, respectively. The gels were prepared based on 3, 4, 5, and 7 molar ratios of carbon to zirconium and heated at 1200 and 1400 °C under vacuum and argon atmospheres. The formation of zirconium carbides under different atmospheres were studied via thermogravimetric analysis and the results were compared. The phase composition and microstructural features were investigated using X-ray diffraction and scanning electron microscopy, respectively. According to the thermogravimetric results and performed thermodynamic calculations, it was revealed that the ZrC formation starts at 1200 °C under vacuum. It is also demonstrated that the formation of nano ZrC powder with crystallite sizes smaller than 30 nm, completely occurs after processing at 1400 °C in vacuum. The measured lattice parameter value of the optimized sample was equal to 4.7003 Å.