Showing 17 results for Sarpoolaky
B. Alinejad1,, H. Sarpoolaky1,, A. Beitollahi1, S. Afshar2,
Volume 4, Issue 1 (winter & spring 2007 2007)
Abstract
Abstract: Nanocrystalline MgAl2O4 spinel powder was synthesized using metal nitrates and a
polymer matrix-based composed of sucrose and polyvinyl alcohol (PVA). The precursor and the
calcined powders were characterized by simultaneous thermal analysis (STA), X-ray diffraction
(XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy
(SEM). According to XRD results, the inceptive formation temperature of spinel via this technique
was between 600°C and 700°C. The average crystallite size of calcined powder at 800°C for 2h
was in the range of 8-12nm. In addition, SEM micrograph showed that the synthesized powder had
a spherical morphology.
A. Ahmadi,, H. Sarpoolaky,, A. Mirhabibi, F. Golestani-Fard,
Volume 4, Issue 3 (Summer &Autumn 2007 2007)
Abstract
Abstract: Dolomite based refractories are widely used in Iranian steelmaking plants. In the
present research, wear and corrosion of refractories used in steel-making converter lining in
Esfahan Steel Company was studied. Post-mortem analysis of refractories clarified that the wear
started with oxidation of carbon followed by chemical corrosion. Iron oxide from slag reacted with
calcia, resulting in formation of low melting phase, and subsequent washout process, caused the
refractory corrosion onset from the hot face. In addition, the effect of aluminum as an anti-oxidant
and graphite on the corrosion resistance of refractory was investigated. Tar-dolomite samples
containing different amount of graphite (0, 4, 7, and 10 wt. %) were prepared in order to study
their physical properties, before and after coking. SEM micrographs employed to analyze the
microstructures to determine the effect of graphite and antioxidant on corrosion behavior of the
refractory. Results showed that oxidation process of carbon in the system was hindered and
improved corrosion resistance by introducing graphite and antioxidant into the refractory
composition.
M. Khosravi Saghezchi, H. Sarpoolaky, F. Heshmatpour,
Volume 5, Issue 2 (spring 2008 2008)
Abstract
Abstract: Lead-containing glass borosilicate was synthesized by Sol-gel technique using
metalalkoxids such as tetraethyleorthosilicate (TEOS), Al-sec-butoxide and trimethyl borate. The
sol containing TEOS converts to gel during drop wise addition of Al-alkoxide while inorganic lead
salt was added in the last stage of gelation to prepare the alcogels. The specimens were dried at
room temperature to set then heated at 600°C quickly to avoid crystallization preparing a glass
containing 63 wt% lead oxide. The influence of pH on absorption behavior of the sols studied by
UV visible technique so the characteristic of the gel, alcogel and xerogel were studied in the
different acidic concentrations. The UV spectrums show that the higher the acidity of the
hydrolysis stages, the higher the absorbance. The results showed the sample with 63 wt% lead was
found fully amorphous. Microstructure and phase analysis of the glass powders were investigated
by X-ray diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM)
equipped with EDS analysis.
N. Hamedani Golshan,, H. Sarpoolaky, A. R. Souri,
Volume 8, Issue 1 (winter 2011 2011)
Abstract
Abstract: Efforts have been carried out in order to use microsilica to develop a forsterite bond rather than other types of binders in the basic refractory castables. According to the higher drying rate and sinterability of colloidal silica, it has been proposed in the recent years. In the present work, effects of replacement of microsilica by colloidal silica evolution of forsterite bond have been studied in magnesia based refractory castables. In this way, Physical properties of prepared samples with different amount of colloidal silica versus temperature were investigated. In addition, phase variation and microstructural evolution of sintered specimens at 1000, 1200 and 1400 °C were studied by X-ray diffraction (XRD) and scanning electron microscope (SEM) respectively. Results showed that, due to Reaction of magnesia with microsilica and colloidal silica, magnesium hydrate and magnesium silicate hydrate formed in the dried samples strengthening the texture of the samples while forsterite formed from about 1000 °C and gradually increased with temperature rise. Also, better forsterite formation would be appeared by increasing the colloidal silica content. Further investigation carried out on the type of silica addition on properties of the castable refractory samples. It was found that the presence of micro silica and colloidal silica simultaneously (MS3C3 sample) at 1400 °C, caused modifying mechanical strength in compare with sample with only micro silica (MS sample).
F. Kashaninia, H. Sarpoolaky, A. R. Bagheri, R. Naghizadeh, M. Zamanipour,
Volume 8, Issue 4 (december 2011)
Abstract
Abstract: There have been lots of studies to control the poor hydration resistance of dolomite refractories one of the
most effective solutions has been the addition of magnesia to doloma. Using a co-clinker of magnesia-doloma as a
starting material would provide more homogeneity in the properties of the product and has been published recently.
On the other hand, addition of iron oxide to doloma has been found to increase the hydration resistance. In this paper,
the effect of iron oxide addition on hydration phase analysis and microstructure of two different magnesia- doloma
samples, one with CaO content of 25 wt% and the other one with that of 35 wt% has been investigated. Ten samples
were prepared by pressing followed by firing at 1750 ºC for 3hrs. Results showed that the hydration resistance of the
samples improved by decreasing the CaO content, because CaO is much more prone to hydration comparing to MgO.
Besides, iron oxide addition lead to the formation of iron-containing phases which increased the hydration resistance
of the samples both by capsulating the CaO and MgO grains and by promoting the liquid phase sintering.
H. Yaghoubi, H. Sarpoolaky, F. Golestanifard, A. Souri,
Volume 9, Issue 2 (june 2012 2012)
Abstract
Colloidal silica bonded refractory castables have been developed recently. It was found that colloidal silica is one of the best binders can substitute other binders such as cement in No Cement Castable (NCC) and Ultra Low Cement Castable (ULCC) refractories. Also composition of colloidal silica with appropriate additives resulted in a gel form which makes the initial strength. Moreover, the nano size silica particles are extremely reactive in high alumina castables and may encourage the mullite formation in the microstructure. In the current study, four castables were prepared. The sample containing 6wt % microsilica was a reference, then microsilica was replaced by different amount of colloidal silica (2.5, 5, 7.5 wt %). Silica and water content was kept constant. It’s concluded that the castables containing the optimum amount of silica sol shows remarkable increase in both castable fluidity and mechanical strength (CCS and MOR) in dried and sintered state. It was also found that nanosilica particles increase the rate of needle-shaped mullite formation during sintering at 1400°C. According to FTIR results, the addition of Calcium Aluminate Cement (CAC) to the silica sol may be responsible for the increment of siloxane bridges (Si-O-Si).
V. Tajer-Kajinebaf, H. Sarpoolaky, T. Mohammadi,
Volume 10, Issue 1 (march 2013)
Abstract
Abstract:Nanostructured titania was synthesized by colloidal and polymeric sol-gel routes. Stable colloidal and polymeric titania sols were prepared by adjusting the proper values of the acid/alkoxide and the water/alkoxide molar ratios. The properties of sols were determined by dynamic light scattering technique and synthesized titania was characterized by thermogravimetry and differential thermal analysis, X-ray diffraction, Fourier transform infrared spectroscopy, optical microscopy and field emission scanning electron microscopy. The results showed particle size distribution of colloidal sol 10-50 nm compared to polymeric one which was 0.5-2 nm. Phase analysis of the colloidal sample revealed anatase as the major phase up to 550 °C, while the polymeric route resulted only anatase phase up to 750 °C. On the basis of results, titania prepared by the polymeric route showed better thermal stability against phase transformation than the sample prepared by the colloidal route. Also, microstructural studies showed that titania nanopowder can be produced by both sol-gel routes
M. S. Saghian, R. Naghizadeh, H. Sarpoolaky,
Volume 10, Issue 2 (June 2013)
Abstract
In this study, the effect of different parameters such as time and temperature of calcination and milling on the formation of calcium aluminosilicates was investigated. Raw materials used in this study were calcium carbonate and kaolin in high purity. Powder X-ray diffraction patterns were obtained from all samples after heat treatment at various temperatures and times. To study the microstructure scanning electron microscope was used. Milling the samples contributed to the amorphous structure due to inducing defects in the structure. Moreover, increasing the milling time reduced crystallization temperature of anorthite. Uptake experiments were performed using solutions containing different concentrations of nickel. Samples were exposed to the solution for 24 h with stirring then the samples were filtered and the concentrations of the cations in the separated solutions were analyzed. FTIR analysis was conducted on the adsorbents before and after nickel uptake. Nevertheless, they hardly helped understand sorption mechanisms. Therefore, adsorption isotherms were studied instead. Three adsorption isotherms of Langmuir, Freundlich and DKR were used to model sorption data. Results suggested monolayer sorption occurs on the surface of the adsorbent and sorption energy calculated by DKR model was 22.36 kJ/mol which can be described as a strong chemical adsorption mechanism
A. R. Amini, A. R. Zakeri, H. Sarpoolaky,
Volume 12, Issue 3 (September 2015)
Abstract
In this paper, the effect of MgO, BaO, Na
2
O and SrO addition to a pre-melted CaO-Al2O3
-Si
2
O synthetic
slag on sulfur removal from plain carbon steel was studied under the same experimental conditions. The slags were
pre-melted at 1400°C in an electric resistant furnace and desulfurization experiments were carried out in a high
frequency induction furnace. The results showed that the optimum reaction time for desulfurization was 15 min. It was
found that while SrO addition to the ternary slag enhances the sulfur removal capability, MgO, Na
2O and BaO
additions reduce desulfurization efficiency of the ternary slag. Moreover, it was observed that restricting access to
oxygen from the atmosphere by using a covered crucible, could increase desulfurization efficiency of the slag by more
than two fold
M. Khosravi Saghezchi, R. Ajami, M. Biazar Markie, H. Sarpoolaky,
Volume 12, Issue 4 (December 2015)
Abstract
A comparing study on formation and microstructure features of aluminum titanate is investigated through both solid-state and sol-gel processes. Aluminum titanate formed by firing at 1350ºC and 1450ºC for 4h in solid-state process. In the sol-gel process formation of submicron sized particles is followed by addition of sucrose into the transparent sol. XRD analysis was confirmed the formation of aluminum titanate at 1400ºC in lower duration of calcination (3h) without any additives in the sol-gel process. In this work 2wt% MgO is added to the samples as the additive for forming acceleration of aluminum titanate. The influence of MgO addition and heat treatment are studied on phase formation and microstructure development of aluminum titanate in both procedures. Additive optimizes aluminum titanate formation at lower temperatures (1300-1350ºC). Phase and microstructure studies of Mg containing samples optimally show significance in aluminum titanate formation.
M. Karimi Sahnesarayi, H. Sarpoolaky, S. Rastegari,
Volume 16, Issue 2 (June 2019)
Abstract
In this study nanosized TiO2coatings on the 316L stainless steel substrate were prepared by means of dip-coating technique in which thickness of the coating layer increased byrepeating the coating cycles in two different routes: (I) dipping and drying,respectively, were repeated one, three and five times and finally the dried coated sample was heat treated (single); (II) multiple heat treatment performed after each dipping and drying cycle, respectively.The structural, morphological and optical characterizations of coatings as well as thickness of coatings were systematically studied.The photocatalytic activity of the various TiO2 coatings was investigated based on the degradation of an aqueous solution of Methyl orange.Moreover, thecorrosion protective properties of coatings were evaluated in both dark and UV illumination conditions based on the obtained polarization curves. The results indicated 1.75 times improvement in photocatalytic reaction rate constant, a two orders of magnitude decrease in corrosion current density in dark condition and about 140 mV electrode potential reduction under UV illumination with optimum coating preparation procedure, repeating the cycle from dipping to heat treatment three times, than the sample prepared with one time coating and heat treatment since this procedure provided not only high thickness and defect-free coating but also transparent one.
V. Tajer Kajinebaf, M. Zarrin Khame-Forosh, H. Sarpoolaky,
Volume 17, Issue 1 (March 2020)
Abstract
In this research, the nanostructured titania-coated silica microsphere (NTCSM) membrane consisting of titania-silica core-shell particles on α–alumina substrate was prepared by dip-coating method. The silica microspheres were synthesized by the Stöber method, and the nanostructured titania shell was obtained from a polymeric sol. Then, the prepared core-shell particles were deposited on alumina substrates. The samples were characterized by DLS, TG-DTA, XRD, FTIR and SEM. The photo-catalytic activity of the NTCSM membranes was evaluated using photo-degradation of methyl orange solution by UV–visible spectrophotometer. Also, physical separation capability was investigated by filtration experiment based on methyl orange removal from aqueous solution using a membrane setup. The mean particle size distribution of silica microspheres was determined to be about 650 nm that by deposition of titania nano-particles increased up to about 800 nm. After 60 min UV-irradiation, the dye removal efficiency was determined to be 80% by the membrane. By coupling separation process with photo-catalytic technique, the removal efficiency was improved up to 97%. Thus, the NTCSM membranes showed simultaneous photo-degradation and separation capabilities for dye removal from water.
Mahnaz Mohammadzadeh Mianji, Hossein Sarpoolaky, Mehrnoush Shafiei Sararoudi,
Volume 18, Issue 1 (March 2021)
Abstract
Translucent porcelain with appropriate workability has been considered beneficial for light and shadow to be used in the production of ceramic artworks. In addition, using low firing temperature encourages more artists to use this body. The soft-paste cellulose composite porcelain is composed of similar amount of high Borax/Calcia leadless frit and Kaolin with 3% Vee gum T as a plasticizer. In order to increase workability and green strength, five units of soft-paste porcelain (SP) slip was mixed by one unit bleached bagasse pulp of sugar cane slip in volume and then cellulose containing soft-paste porcelain (CSP) slip was made. The samples were formed by hand, dried and then fired at the optimum temperature of 1120 for 5 hours. Results showed that the SP sample became self-glazed after firing while cellulose increased porosity in CSP. Microstructure analysis showed a large amount of glass phase, which improved translucency of the bodies. Moreover, mullite needle-shaped crystals were derived from the flux-penetrated clay because of less viscous molten body matrix. XRD results clearly showed that the fritted soft-paste porcelain consists of quartz, mullite, anorthite and albite in the fired state. Spectrophotometry showed that adding cellulose to the porcelain body slightly increased translucency in the wavelength ranges 400 to 500 nm.
Sara Ahmadi, Bijan Eftekhari Yekta, Hossein Sarpoolaky, Alireza Aghaei,
Volume 18, Issue 4 (December 2021)
Abstract
In the present work, monolithic gels were prepared through different drying procedures including
super critical, infrared wavelengths and traditional drying methods. Dense and transparent glasses
were obtained after controlled heat treatment of the dried porous xerogels in air atmosphere.
The chemical bonding as well as different properties of the prepared gels and the relevant glasses
were examined by means of Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmitt-
Teller (BET) and UV-Vis spectrometer. Based on the obtained results, different drying conditions
affect the average pore size and the total pore volume of the studied gels. The mean pore size was
found to be 8.7 nm, 2.4 nm and 3.2 nm for super critical, IR radiation and slow drying in air
atmosphere, respectively. The glass network structure was significantly changed by heat treatment temperature so that the B-O-Si bonds were formed only after 450 °C. It was found that the gel dried under super critical condition was unable to reach to its full density all over the selected sintering temperature interval.
Shadi Moshayedi, Hossein Sarpoolaky, Alireza Khavandi,
Volume 19, Issue 2 (June-Biomaterials Special Issue- 2022)
Abstract
In this paper, chemically-crosslinked gelatin/chitosan hydrogels containg zinc oxide nanoparticles (ZNPs), were loaded with curcumin (CUR), and their microstructural features, physical properties, curcumin entrapment efficiency, and drug release kinetics were evaluated using scanning electron microscopy (SEM), the liquid displacement method, and UV–Vis spectroscopy. The in vitro kinetics of drug release was also studied using First-order, Korsmeyer-Peppas, Hixon-Crowell, and Higuchi kinetic models. The SEM micrographs confirmed the formation of highly porous structures possessing well-defined, interconnected pore geometries. A significant reduction in the average pore sizes of the drug-loaded hydrogels was observed with the addition of ZNPs and CUR to the bare hydrogels. High value of drug loading efficiency (~ 72 %) and maximum drug release of about 50 % were obtained for the drug-loaded scaffolds. It was found that curcumin was transported via the non-Fickian diffusion mechanism. It was also shown that the kinetics of curcumin release was best described in order by Hixon-Crowell, Higuchi, and Korsmeyer-Peppas models, demonstrating that drug release was controlled by diffusion, degradation, and swelling of the drug carrier. However, lower degree of fitting was observed with First-order kinetic model.
Amirreza Sazvar, Seyed Mohammad Saeed Alavi, Hossein Sarpoolaky,
Volume 20, Issue 2 (June 2023)
Abstract
We report a simple and practical approach for the easy production of superhydrophobic coatings based on TiO2-SiO2@PDMS. In this study, we used tetraethylorthosilicate (TEOS) and titanium tetraisopropoxide (TTIP) as a precursor for the sol-gel synthesis of SiO2 and TiO2, respectively. Afterward, the surface of nanoparticles was modified by 1,1,1,3,3,3-hexamethyldisilazane (HMDS) before being combined with polydimethylsiloxane (PDMS). The hydrophobic property of coatings was evaluated by static contact angle measurements. The phase composition and structural evolution of the coatings were examined by X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analysis. It was shown that changing the weight ratio of the solution composition of the coating can affect the hydrophobicity of the surface. The best sample has shown a superhydrophobic property with a 153˚ contact angle which contained (75%TiO2-25%SiO2) and PDMS at a weight ratio of 1:1. Moreover, the results showed that the superhydrophobic coating retains its hydrophobic properties up to a temperature of 450 ˚C, and at higher temperatures, it converts to a super hydrophilic with a water contact angle close to 0 ˚. The SiO2-TiO2@PDMS coating degrades methylene blue by about 55% and was shown to be capable of photocatalytically decomposing organic pollutants.
Hamed Nadimi, Hossein Sarpoolaky, Mansour Soltanieh,
Volume 20, Issue 4 (December 2023)
Abstract
In the present investigation, an attempt was made to evaluate the dissolution behavior of Ti in molten KCl-LiCl. The X-ray diffraction (XRD) pattern of heated Ti plate at 800 oC for 4 h without carbon black in molten salt revealed that TiCl3 formation was feasible. For more assurance, Ti plate was heated at 950 oC for 4 h in the presence of carbon black to identify synthesized TiC. Transmission electron microscope (TEM) and scanning electron microscope (SEM) images from precursors and the final product showed that nano-crystalline TiC formation from coarse Ti particles was almost impossible without Ti dissolution. Thermodynamics calculations using Factsage software proved that it was possible to form various TiClx compounds. The TiC formation mechanism can be discussed in two possible ways: a reaction between Ti ion and carbon black for synthesizing TiC (direct) and a reaction between TiCl4 and carbon black led to indirect TiC synthesis. Elemental mapping using energy dispersive X-ray spectroscope (EDS) indicated that up to 815 oC, chlorine existed in the map.
