Journal articles: 'Sol-Air Temperatures'

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Isshiki, Yasuhiro, Kaoru Dokko, Jun Ichi Hamagami, Takashi Takei, and Kiyoshi Kanamura. "Preparation of Lithium Ion Conductive Li_4.2Al_0.2Si_0.8O₄ Thin Films Using Sol-Gel Process." Key Engineering Materials 301 (January 2006): 91–94. http://dx.doi.org/10.4028/www.scientific.net/kem.301.91.

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Thin films of lithium ion conductive ceramic Li4+xAlxSi1-xO4 were fabricated on Au substrate using sol-gel process. The sol of Li-Al-Si-O was spread on Au substrate using a spin coater, and it was gelated at room temperature. The gel was calcinated at 400 °C and heat-treated at high temperatures between 500 °C and 800 °C in air. The addition of poly(vinylpyrrolidone) (PVP) was effective in stabilizing the sol. Furthermore, the morphology of the obtained thin film was changed by the PVP additive. Li4+xAlxSi1-xO4 thin film prepared at 800 °C exhibited a Li+ ion conductivity of 10-8 S cm-1 at room temperature.

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Song, Qiu Sheng, Kai Zhang, Shun Xu, Zhen Biao Zhong, and Meng Li. "Porous SiO₂/SiC Fiber Via Carbothermal-Reduction of Hybrid Fiber in Air Flows." Advanced Materials Research 236-238 (May 2011): 1492–96. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.1492.

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Using tetraethoxysilane (TEOS) and novolac-PF as raw materials, SiO2/PF hybrid fibers were prepared via sol-gel associated with drawing process, and then sintered at different temperatures (500-1300 °C) under air atmosphere. The microstructure variation and reaction mechanism of the fiber were investigated by FT-IR, XRD, and SEM measurements. The results showed that the microstructure variation of the hybrid fiber was influenced greatly by sintering temperatures. When the sintering temperature was below 900 °C, the fibers were amorphous, and converted into porous SiO2/SiC fibers after being sintered at 1300 °C.

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Tseng, Ching Fang, Cheng Hsing Hsu, and Chun Hung Lai. "Dielectric Properties of Sol-Gel Derived MgAl₂O₄ Thin Films." Applied Mechanics and Materials 151 (January 2012): 314–18. http://dx.doi.org/10.4028/www.scientific.net/amm.151.314.

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This paper describes microstructure characteristics of MgAl2O4 thin films were deposited by sol-gel method with various preheating temperatures and annealing temperatures. Particular attention will be paid to the effects of a thermal treatment in air ambient on the physical properties. The annealed films were characterized using X-ray diffraction. The surface morphologies of treatment film were examined by scanning electron microscopy and atomic force microscopy. At a preheating temperature of 300oC and an annealing temperature of 700oC, the MgAl2O4 films with 9 μm thickness possess a dielectric constant of 9 at 1 kHz and a dissipation factor of 0.18 at 1 kHz.

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Garníca-Romo, M. G., J. González-Hernández, M. A. Hernández-Landaverde, Y. V. Vorobiev, F. Ruiz, and J. R. Martínez. "Structure of heat-treated sol-gel SiO2 glasses containing silver." Journal of Materials Research 16, no. 7 (July 2001): 2007–12. http://dx.doi.org/10.1557/jmr.2001.0275.

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The crystallization of bulk amorphous SiO2 samples, prepared by the sol-gel method, was obtained by heat treatments in air at temperatures as low as 500 °C. This occurs when silver is added to the precursor solutions in an amount such that it forms aggregates embedded in the glass. Another requirement to observe the low-temperature glass crystallization is that the bulk samples must be prepared from precursor solutions with specific compositions. These compositions, have a high H2O/TEOS ratio, which produces an amorphous SiO2 structure with some structural similarities to cristobalite, the phase in which the SiO2 glass crystallizes.

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Hsu, Cheng Hsing, Jenn Sen Lin, and His Wen Yang. "Fabrication and Characterization of MgAl₂O₄ Thin Films by Sol-Gel Method." Advanced Materials Research 216 (March 2011): 514–17. http://dx.doi.org/10.4028/www.scientific.net/amr.216.514.

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This paper describes microstructure characteristics of MgAl2O4 thin films were deposited by sol-gel method with various annealing temperatures. Particular attention will be paid to the effects of an annealing treatment in air ambient on the physical properties. The annealed films were characterized using X-ray diffraction. The surface morphologies of annealed film were examined by scanning electron microscopy and atomic force microscopy. The dependence of the dielectric properties and microstructure characteristics on annealing temperature was also investigated.

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Wu, Han Shui, and Ying Lian Wang. "Preparation and Photocatalytic Properties of ZnO Thin Films." Advanced Materials Research 951 (May 2014): 96–99. http://dx.doi.org/10.4028/www.scientific.net/amr.951.96.

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Highly photoactive ZnO thin films on glass substrates and quartz substrates have been prepared by sol-gel process. Structural features, surface morphology and UV absorption spectrum have been studied by XRD, SEM and UV-Vis scanning spectrophotometer. The influence of degradation temperatures, original concentration of phenol and air flux on degradation rates have also been studied. And the results show the best conditions, degradation temperature is between 25oC and 45 oC, air flux is 40ml/min, the lower original concentration, the higher degradation rates. Excellent adhesion as well as recyclable and efficient in phenol degradation of ZnO thin films were found in this experiment.

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Tseng, Ching Fang, Yun Pin Lu, Hsin Han Tung, and Pai Chuan Yang. "Effect of Annealing Treatments on the Physical Characteristics of (Ca_0.8Sr_0.2)TiO₃ Thin Films by Sol-Gel Method." Key Engineering Materials 512-515 (June 2012): 1171–74. http://dx.doi.org/10.4028/www.scientific.net/kem.512-515.1171.

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This paper describes physical properties of (Ca0.8Sr0.2)TiO3 were deposited by sol-gel method with a fix per-heating temperature of 400oC for 60 min at various annealing temperatures from 600oC to 700oC for 60 min. Particular attention will be paid to the effects of an annealing treatment in air ambient on the physical properties. The annealed films were characterized using X-ray diffraction (XRD). The surface morphologies of annealed film were examined by atomic force microscopy and scanning electron microscopy.

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Ruiz, F., J. R. Martínez, and J. González-Hernández. "Formation of silicate structures in Cu-containing silica xerogels." Journal of Materials Research 15, no. 12 (December 2000): 2875–80. http://dx.doi.org/10.1557/jmr.2000.0410.

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Using infrared absorption and Raman spectroscopy, the structure of SiO2 sol-gel samples containing copper were analyzed as a function of air heat treatments. The weight composition of the samples was 70(SiO2)–30(CuO) and the thermal treatments were carried out in air at various temperatures in the range of 100–600 °C. It was found that the Cu might be incorporated into the SiO2 matrix at least in two ways: forming oxide particles and forming metasilicatelike structures. The copper metasilicate found had the chemical formula, Cu6 [Si6O18] · 6H2O, which is known as dioptase with a thermal stability at temperatures up to 600 °C.

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Myasoedova, T. N., Victor V. Petrov, Nina K. Plugotarenko, Dmitriy V. Sergeenko, Galina Yalovega, Mariya M. Brzhezinskaya, and Evgeniya N. Shishlyanikova. "SiO₂ZrO₂ Thin Films as Low Temperature NO₂ and O₃ Sensors." Advanced Materials Research 1088 (February 2015): 81–85. http://dx.doi.org/10.4028/www.scientific.net/amr.1088.81.

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Thin SiO2ZrO2films were prepared, up to 0.2 μm thick, by means of the sol–gel technology and characterized by a Scanning electron microscopy and X-ray diffraction. It is shown the presence of monoclinic, cubic and tetragonal phases of ZrO2in the SiO2matrix. The crystallites sizes depend on the annealing temperature of the film and amount to 35 and 56 nm for the films annealed at 773 and 973 K, respectively. The films resistance is rather sensitive to the presence of NO2and O3impurity in air at lower operating temperatures in the range of 30-60°C.

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WIDYASTUTI, WIDYASTUTI, FELLY YULIAN FF, ROCHMAN R, and HARIYATI PURWANINGSIH. "SYNTHESIS OF NANOPARTICLE BARIUM HEX AFERRITE BY SOL GEL AUTO COMBUTIO." Jurnal Teknik Industri 12, no. 2 (February 18, 2012): 156. http://dx.doi.org/10.22219/jtiumm.vol12.no2.156-161.

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Nanocrystalline of Barium Hexaferrite (BaFe12O19) powders have been synthesized using the sol gel auto combustion method. The ferrite precursors were obtained from aqueous mixtures of Barium nitrate and Ferric nitrate by auto combustion reaction from gel point. These precursors were sintered at different temperatures ranging from 700 to 1000oC for constant calcinations time 2,5 h in a static air atmosphere. Effects of Fe3+/Ba2+ mol ratios and sintering temperatures on the microstructure and magnetic properties were systematically studied. The powders formed were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM) and VSM. The results obtained showed that the phase BaFe12O19 powders were achieved by the Fe3+/Ba2+ mole ratio from the stoichiometric value 11, 11.5 and 12 at temperature950OC. With increasing of temperature sintering, coercivity and magnetization value tends to rising. The maximum saturation magnetization (66.16 emu/g) was achieved at the Fe3+/Ba2+mole ratio to 11.5 and the sintering temperature 950OC. The maximum coercivity value 3542 Oe achieved at mole ratio sample 12 with sintering temperature 950OC. Maximum saturation 6616 emu/g achieved at mole ratio sample 115 with the same temperature.

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Basinova, Nikola, Ondrej Cernohorsky, Jan Grym, Sarka Kucerova, Hana Faitova, Roman Yatskiv, Jan Vanis, Jozef Vesely, and Jaroslav Maixner. "Highly Textured Seed Layers for the Growth of Vertically Oriented ZnO Nanorods." Crystals 9, no. 11 (October 30, 2019): 566. http://dx.doi.org/10.3390/cryst9110566.

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One dimensional ZnO nanostructures prepared by favorable and simple solution growth methods are at the forefront of this research. Vertically oriented ZnO nanorods with uniform physical properties require high-quality seed layers with a narrow size distribution of the crystallites, strong c-axis orientation, and low surface roughness and porosity. It has been shown that high quality seed layers can be prepared by the sol–gel process. The sol–gel process involves three essential steps: preparation of the sol, its deposition by dip coating, and thermal treatment comprising preheating and annealing. We put emphasis on the investigation of the heat treatment on the properties of the seed layers and on the vertical alignment of the nanorods. It was demonstrated that for the vertical alignment of the nanorods, the preheating step is crucial and that the temperatures reported in the literature have been too low. With higher preheating temperatures, conditions for the vertical alignment of the nanorods were achieved in both investigated annealing atmospheres in air and in argon.

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AKCALI, KADRİ, and MELİHA OKTAV BULUT. "A new finishing process of cotton fabric." Industria Textila 70, no. 02 (May 1, 2019): 101–10. http://dx.doi.org/10.35530/it.070.02.1513.

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Ecological and economic responsibilities have led to the search for alternative material applications in the textile sector as well as in all sectors. Sol-gel technology is one of these applications with advantages such as realization under low temperatures and enabling the desired product shape and format. In this study, the samples of 100% cotton fabric have been processed by using pigment printing technique with natural pumice, amorphous silica and colemanite materials and printing fixation process has been performed by using the sol gel coating method. The sol gel treatment has been carried out with basic catalyst according to the zeta potentials of the solid particulate materials used. After the new created process, surface morphologies, EDS point analysis and F-TIR analysis of all fabric samples have been performed. In addition, the properties such as strength, UV protection, air permeability, water permeability, abrasion resistance, flammability of all fabrics have been investigated. The results of surface analysis have proven that the chemical components of the natural materials are transferred to the fabric samples. It has been proven by the test results that all cotton fabric samples are given high strength, UV protection, flammability, high abrasion resistance and low air permeability. Interpretation of all the analysis and obtained test results has been also made statistically. According to the study results, ecofriendly process step has been created that allows low energy cost and low chemical usage under low temperatures

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13

Tiwari, V. S., Arun Kumar, V. K. Wadhawan, and Dhananjai Pandey. "Kinetics of formation of the pyrochlore and perovskite phases in sol-gel derived lead zirconate titanate powder." Journal of Materials Research 13, no. 8 (August 1998): 2170–73. http://dx.doi.org/10.1557/jmr.1998.0303.

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Lead zirconate titanate (PZT) powder is prepared by the sol-gel method. The formation of pyrochlore and perovskite phases is investigated by high temperature x-ray diffraction (XRD) and thermal analysis techniques. The pyrochlore phase first appears in x-ray amorphous form, and then gets converted to crystalline state on annealing in air. We show that vacuum annealing of the pyrolyzed amorphous PZT gel suppresses the formation of the crystalline pyrochlore phase. This, in turn, enhances the kinetics of conversion of pyrochlore to perovskite, such that a pyrochlore-free perovskite phase can be obtained by annealing at about 500 °C. On the other hand, if annealing is carried out in air, a crystalline pyrochlore phase is formed, which requires annealing temperatures higher than 600 °C for transformation to the perovskite phase. These observations are explained tentatively in terms of the oxygen stoichiometry of the two phases.

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Halin, Dewi Suriyani Che, Ibrahim Abu Talib, Abdul Razak Daud, and Muhammad Azmi Abdul Hamid. "Effect of Annealing Atmosphere on the Morphology of Copper Oxide Thin Films Deposited on TiO₂ Substrates Prepared by Sol-Gel Process." Key Engineering Materials 594-595 (December 2013): 113–17. http://dx.doi.org/10.4028/www.scientific.net/kem.594-595.113.

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Copper oxide films were prepared via sol-gel like spin coating starting from methanolic solutions of cupric chloride onto the TiO2 substrates. Films were obtained by spin coating under room conditions (temperature, 25-30 °C) and were subsequently annealed at different temperatures (200-400 °C) in oxidizing (air) and inert (N2) atmospheres. X-ray diffraction (XRD) patterns showed crystalline phases, which were observed as a function of the annealing conditions. The film composition resulted single or multi-phasic depending on both temperature and atmosphere. The grain size of film was measured using scanning electron microscopy (SEM) and the surface roughness of thin films was characterized by atomic force microscopy (AFM). The grain size of which was annealed in air at 300 °C was 30.39 nm with the surface roughness of 96.16 nm. The effects of annealing atmosphere on the structure and morphology of copper oxide thin films are reported.

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Khlayboonme, S. Tipawan, and Warawoot Thowladda. "Effects of Air Exposure Time and Annealing Temperature on Superhydrophobic Surface of Titanium Dioxide Films." Key Engineering Materials 751 (August 2017): 137–42. http://dx.doi.org/10.4028/www.scientific.net/kem.751.137.

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TiO2 thin films coated on glass substrates for self-cleaning applications were prepared by sol-gel dip-coating technique. The influence of annealing temperature and air exposure time on wettability was investigated by a water contact-angle measurement. Thermal annealing at temperatures of 100, 200 and 300 °C in air were conducted to the films. Surface morphology of the films was observed by FE-SEM. Elemental distribution and optical properties were examined by EDX mapping and UV-Vis transmission spectroscopy, respectively. Atomic bonding was confirmed by FTIR. The contact angle reached a maximum when the films were annealed at 200 °C. The contact angles of the as-synthesized films were 61.4±2.7°. During storage in air for 20 days, the contact angles increased to 143.1±2.1°. The films were further reannealed with 100 °C for 20 min, the contact angles were enhanced to 153.1±1.3°. The association of contact angle among the surface morphology, elemental distribution and atomic bonding of the films will be discussed.

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16

Yarici, I., M. Erol, E. Celik, and Y. Ozturk. "Effect of pH and annealing temperature on the structural and magnetic properties of cerium-substituted yttrium iron garnet powders produced by the sol-gel method." Materials Science-Poland 34, no. 2 (June 1, 2016): 362–67. http://dx.doi.org/10.1515/msp-2016-0036.

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AbstractCerium substituted yttrium iron garnet (Ce0.2Y2.8Fe5O12; Ce-YIG) nanoparticles were produced via the sol-gel method from solutions of Ce-, Y- and Fe-based precursors, a solvent and a chelating agent. The solutions were dried at 200°C and heat treated at temperatures between 800 °C and 1400°C for 3 h in air. The effects of pH and annealing temperature on the structure, phase formation, magnetic properties and crystallite size were investigated. A cubic YIG phase was obtained for the sample annealed at 1400 °C. The presented results showed that the pH value of the starting solution affects the crystal size and consequently, the saturation magnetization.

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Tuval, Tamir, Brian A. Rosen, Jacob Zabicky, Giora Kimmel, Helena Dilman, and Roni Z. Shneck. "Thermal Expansion of MgTiO3 Made by Sol-Gel Technique at Temperature Range 25–890 °C." Crystals 10, no. 10 (October 1, 2020): 887. http://dx.doi.org/10.3390/cryst10100887.

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MgTiO3 is a material commonly used in the industry as capacitors and resistors. The high-temperature structure of MgTiO3 has been reported only for materials synthesized by the solid-state method. This study deals with MgTiO3 formed at low temperatures by the sol-gel synthesis technique. Co-precipitated xerogel precursors of nanocrystalline magnesium titanates, with Mg:Ti ratio near 1:1, were subjected to thermal treatment at 1200 °C for 5 h in air. A sample with fine powders of MgTiO3 (geikielite) as a major phase with Mg2TiO4 (qandilite) as a minor phase was obtained. The powder was scanned on a hot-stage X-ray powder diffractometer at temperatures between 25 and 890 °C. The lattice parameters and the atomic positions of the two phases were determined as a function of temperature. The thermal expansion coefficients of the geikielite were derived and compared with previously published data using the solid-state synthesis technique, providing insights on trends in materials properties at elevated temperature as a function of synthesis. It was found that the deviation of the present results in comparison to previously reported data do not originate from the method of synthesis but rather from the fact that there is an asymmetric solubility gap in geikielite. The lattice parameters of this study present the property of stoichiometric MgTiO3 and are compared to previously reported non-stoichiometric MgTiO3 with excess of Ti. The values of lattice parameters of the non-stoichiometric versus temperature of geikielite found the same for both solid-state reaction and sol-gel products.

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Tu, Y. L., and S. J. Milne. "Characterization of single layer PZT (53/47) films prepared from an air-stable sol-gel route." Journal of Materials Research 10, no. 12 (December 1995): 3222–31. http://dx.doi.org/10.1557/jmr.1995.3222.

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Single layer Pb(Zr0.53Ti0.47)O3 films up to 0.7 μm thick have been prepared from air-stable titanium and zirconium precursors using a diol-based sol-gel route. Information on film crystallization, surface microstructure, and electrical properties under different firing temperatures and three different heating rates including rapid thermal annealing are presented. Films exhibited (111) preferred orientation, the extent of which reduced with increasing firing temperature or heating rate. It is possible that a PbPtx interfacial reaction product was formed during the prefiring step at 350 °C and this, together with the influence of the 111 bottom platinum electrode, contributed to (111) orientation in the PZT films. Surface microstructure was also influenced by firing temperature and heating rate as well as by film thickness. The 0.4 μm thick films used for electrical measurement had a grain size of ⋚0.1 μm, whereas 0.7 μm thick films made from concentrated sols exhibited “rosette” microstructures with grain sizes up to 0.5 μm. Among the three firing schedules studied, directly inserting the gel coatings in a furnace preset at 700 °C produced films with the most favorable electrical properties. A 0.4 μm thick film gave rise to a remanent polarization, Pr, of 33 μC cm−2 coercive field, Ec, of 46 kV cm−1; relative permittivity, ∊r, of 1100; and dissipation factor, D, of 0.05. For a 0.7 μm single layer film, the respective values were 21 μC cm−2, 36 kV cm−1, 1300, and 0.05.

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Calzada, M. L., I. Bretos, R. Jiménez, H. Guillon, J. Ricote, and L. Pardo. "Low-temperature ultraviolet sol-gel photoannealing processing of multifunctional lead-titanate-based thin films." Journal of Materials Research 22, no. 7 (July 2007): 1824–33. http://dx.doi.org/10.1557/jmr.2007.0228.

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(Pb1−xCax)TiO3 perovskite thin films with nominal compositions of (Pb0.76Ca.24)TiO3 (ferroelectric) and (Pb0.50Ca0.50)TiO3 (relaxor-ferroelectric) were prepared on silicon substrates at low temperatures compatible with those used in Si-technology. The technique used for the processing of these films was ultraviolet (UV) sol-gel photoannealing, using photo-sensitive precursor solutions and UV-assisted rapid thermal processing. The UV-irradiation and thermal treatment of the solution-derived films (gel films) were carried out in air or in oxygen. In both cases, the formation of the perovskite occurred at the same temperature, and this temperature increased as the Ca2+ content increased. Thus, full-perovskite films of (Pb0.76Ca.24)TiO3 were obtained at 723 K whereas those of (Pb0.50Ca0.50)TiO3 were formed at 773 K. Well-defined ferroelectric hysteresis loops were measured in the (Pb0.76Ca.24)TiO3 films, with values of remanent polarization of Pr ∼ 11 μC cm−2 and coercive fields for the films processed in oxygen lower than those of the films processed in air, Ec ∼ 164 and ∼226 kV.cm−1, respectively. These films showed a ferro-paraelectric transition at close temperatures of Tmax ∼ 605 K, although with higher values of the permittivity for the film processed in oxygen, k ∼ 567 at 10 kHz. The (Pb0.50Ca.50)TiO3 films had a diffuse ferro-paraelectric transition with a relaxor-like character, also with higher k values for the films prepared in oxygen, k ∼ 179 at Tmax ∼ 20 K. The possible use of these materials in silicon integrated multifunctional devices is discussed in this paper.

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Rowles, Matthew R., Cheng-Cheng Wang, Kongfa Chen, Na Li, Shuai He, and San-Ping Jiang. "Temperature-dependent structural behaviour of samarium cobalt oxide." Powder Diffraction 32, S2 (August 22, 2017): S38—S42. http://dx.doi.org/10.1017/s0885715617000872.

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The crystal structure and thermal expansion of the perovskite samarium cobalt oxide (SmCoO3) have been determined over the temperature range 295–1245 K by Rietveld analysis of X-ray powder diffraction data. Polycrystalline samples were prepared by a sol–gel synthesis route followed by high-temperature calcination in air. SmCoO3 is orthorhombic (Pnma) at all temperatures and is isostructural with GdFeO3. The structure was refined as a distortion mode of a parent $ Pm{\bar 3}m $ structure. The thermal expansion was found to be non-linear and anisotropic, with maximum average linear thermal expansion coefficients of 34.0(3) × 10−6, 24.05(17) × 10−6, and 24.10(18) × 10−6 K−1 along the a-, b-, and c-axes, respectively, between 814 and 875 K.

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Haider, Adawiya, Riyad Al-Anbari, Ghadah Kadhim, and Zainab Jameel. "Synthesis and photocatalytic activity for TiO2 nanoparticles as air purification." MATEC Web of Conferences 162 (2018): 05006. http://dx.doi.org/10.1051/matecconf/201816205006.

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In the present work, titanium dioxide (TiO2) nanoparticles (NP’s) were prepared using sol-gel process from Titanium Tetrachloride (TiCl4) as a precursor with calcinations at two temperatures (500 and 900) °C. The effect of calcinations temperatures on the structural, optical, morphological and Root Mean Square (roughness) properties were investigated by means of Scanning Electron Microscopy, X-ray Diffraction (XRD), and Atomic Force Microscopy (AFM). Bacterial inactivation was evaluated using TiO2-coated Petri dishes. A thin layer of photocatalytic TiO2 powder was deposited on glass substrate in order to investigate the self-cleaning effect of TiO2 nanoparticles in indoor and outdoor applications. Ultra-hydrophilicity was assessed by measuring the contact angle and it evaluated photolysis properties through the degradation of potassium permanganate (KMnO4) under direct sunlight. XRD analysis indicated that the structure of TiO2 was anatase at 500 °C and rutile at 900 °C calcination temperatures. As the calcination temperature increases, the crystallinity is improved and the crystallite size becomes larger. Coated films of TiO2 made the has permeability, low water contact angle and good optical activity. These are properties essential for the application of the surface of the self-cleaning. The final results illustrate that titanium dioxide can be used in the build materials to produce coated surfaces in order to minimize air pollutants that are placed in microbiologically sensitive circumference like hospitals and the food factory.

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Zhao, Ming, Li Hui Sun, Ji Fan Hu, and Hong Wei Qin. "CO Sensing Properties of La1-xCaxFeO3 Perovskite Nanocrystalline Materials." Key Engineering Materials 495 (November 2011): 323–26. http://dx.doi.org/10.4028/www.scientific.net/kem.495.323.

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The La1-xCaxFeO3 nanocrystalline powders were prepared by sol-gel method. These powders crystallized as perovskite orthorhombic structure. With an increase of Ca content, the resistance of La1-xCaxFeO3 sensors in air decreases at first, undergoes a minimum at x=0.3, and then increases again. La1-xCaxFeO3-based sensors show sensitive responses to CO. Among those La1-xCaxFeO3-based sensors, the sensor with x=0.2 shows the highest response to 200 ppm CO at operating temperatures below 325°C. The highest response S=(RCO-Rair)/RCO for the La0.8Ca0.2FeO3 based sensor to 200 ppm CO is 87% with response time 15 s and recovery time 60 s at an operating temperature of 100°C.

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Rezaee, S., Gh R. Rashed, and M. A. Golozar. "Electrochemical and Oxidation Behavior of Yttria Stabilized Zirconia Coating on Zircaloy-4 Synthesized via Sol-Gel Process." International Journal of Corrosion 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/453835.

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Sol-gel 8 wt.% Yttria Stabilized Zirconia (YSZ) thin films were prepared on zirconium (zircaloy-4 alloy) by dip-coating technique followed by heat treating at various temperatures (200°C, 400°C, and 700°C) in order to improve both electrochemical corrosion and high temperature oxidation properties of the substrate. Differential thermal analysis and thermogravimetric analysis (DTA-TG) revealed the coating formation process. X-ray diffraction (XRD) was used to determine the crystalline phase structure transformation. The morphological characterization of the coatings was carried out using scanning electron microscopy (SEM). The electrochemical behavior of the coated and uncoated samples was investigated by means of open circuit potential, Tafel, and electrochemical impedance spectroscopy (EIS) in a 3.5 wt.% NaCl solution. The homogeneity and surface appearance of coatings produced was affected by the heat treatment temperature. According to the corrosion parameters, the YSZ coatings showed a considerable increase in the corrosion resistance, especially at higher heat treatment temperatures. The coating with the best quality, from the surface and corrosion point of view, was subjected to oxidation test in air at 800°C. The coated sample presented a 25% reduction in oxidation rate in comparison with bare substrate.

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LIU, YAQIANG, XUELIAN DU, and XUEQIN LIU. "EFFECT OF ANNEALING ON THE PROPERTIES OF VANADIUM PENTOXIDE FILMS PREPARED BY SOL–GEL METHOD." Surface Review and Letters 21, no. 02 (April 2014): 1450027. http://dx.doi.org/10.1142/s0218625x14500279.

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The vanadium pentoxide ( V 2 O 5) films were obtained by using sol–gel procedure and then were annealed at different temperature in air. The effect of different annealing temperatures on the composition, the microstructure, the surface morphology and the optical properties of the films were characterized by methods such as by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and spectral transmittance. The results revealed that the film annealed at 150°C has amorphous structure and dense with a smooth surface and the films annealed at 300°C and 450°C have a polycrystalline V 2 O 5 structure with preferred growth orientation along (001) planes, the c-axis and perpendicular to the silicon substrate surface. From the spectral transmittance we determined the absorption edge using the Tauc plot. The results indicated that optical bandgap of V 2 O 5 thin films decreased with annealing temperature.

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Shaiboub, Ramadan E., and N. B. Ibrahim. "Characterization of Erbium Substituted Yttrium Iron Garnet Films Prepared by Sol-Gel Method." Journal of Nanoscience 2014 (April 6, 2014): 1–5. http://dx.doi.org/10.1155/2014/158946.

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Yttrium iron garnet (YIG) thin films substituted erbium ions (Er+3) Er0.4Y2.6Fe5O12 films were prepared by a sol-gel method at different temperatures which varied from 800 to 1000°C for 2 hours in air. Magnetic and microstructural properties of the films were characterized with X-ray diffraction (XRD), the field emission scanning electron microscopy (FESEM), and vibrating sample magnetometer (VSM). The XRD patterns of the sample have only peaks of the garnet structure. The lattice constants decrease, while the particle size increases from 51 to 85 nm as the annealing temperature increases with average in thickness of 300 nm. The saturation magnetization and the coercivity of the samples increased from 26 (emu/cc) and 28 Oe for the film annealed at 800°C to 76 (emu/cc) and 45 Oe for film annealed at 1000°C, respectively.

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Tadjiev, Timur R., Sung Su Chun, Hong Mi Kim, Inn Kyu Kang, and Suk Young Kim. "Preparation and Characterization of Calcium Metaphosphate Nanofibers via Electrospinning." Key Engineering Materials 330-332 (February 2007): 207–10. http://dx.doi.org/10.4028/www.scientific.net/kem.330-332.207.

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Bioresorbable calcium metaphosphate (CMP) nanofibers were produced by an electrospinning technique. In order to produce the nanofibers, CMP sol was prepared by the mixing of two precursors, such as calcium nitrate tetrahydrate (Ca[NO3]⋅4H2O) and triethyl phosphate (TEP, [C2H5O]3PO), using methyl alcohol as a solvent. The Ca/P ratio of the mixture was set to be 0.50 to produce stoichiometric CMP sol. At least 5 hrs of pre-hydrolysis of phosphorus precursor were required to obtain β-CMP phase. Viscous solutions for the electrospinning were made by the mixing of CMP sol and high-molecular weight polymeric solution at various ratios. The ratio of CMP sol and polymer solution was controlled to obtain an appropriate viscosity for the electrospinning. As-electrospun CMP nanofibers were dried in a drying oven at 70°C for 24 hrs and then heat-treated at various temperatures at a ramp of 1°C/min in air for 1hr. The as-electrospun and heat-treated CMP nanofibers were characterized using X-ray analysis, FT-IR, TG-DTA and SEM techniques. The results showed that the preparation of CMP sol, mixed solution properties, and heat-treatment condition of as-electrospun nanofibers significantly affect the spinability and surface morphology of the CMP nanofibers.

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Fedoriv, V. D., L. V. Turovska, I. P. Yaremiy, and N. V. Stashko. "Crystalquasichemical Description the Formation of Defects in nanodispersed Yttrium-Iron Garnet." Фізика і хімія твердого тіла 17, no. 4 (December 15, 2016): 621–24. http://dx.doi.org/10.15330/pcss.17.4.621-624.

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By the sol-gel method of autocombustionan initial oxide system was synthesized for a receipt a nanodispersed Yttrium Iron Garnet. It was set that forming of the monophase system Y3Fe5O12 begins at temperatures above 973 К in static air atmosphere. The crystalquasichemical formulas for Y3Fe5O12 are offered. Dependence of concentration of defects from a degree non-stoichiometry of oxygen is calculated. It was set that the formation of garnet structure needed oxygen atmosphere annealing. Partial pressure of oxygen determines the resulting structure defects.

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Rahayu, Sri, Jennifer S. Forrester, Girish M. Kale, and Mojtaba Ghadiri. "Promising solid electrolyte material for an IT-SOFC: crystal structure of the cerium gadolinium holmium oxide Ce0.8Gd0.1Ho0.1O1.9 between 295 and 1023 K." Acta Crystallographica Section C Structural Chemistry 74, no. 2 (January 30, 2018): 236–39. http://dx.doi.org/10.1107/s2053229617017946.

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The crystal structure of Ce0.8Gd0.1Ho0.1O1.9 (cerium gadolinium holmium oxide) has been determined from powder X-ray diffraction data. This is a promising material for application as a solid electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFCs). Nanoparticles were prepared using a novel sodium alginate sol-gel method, where the sodium ion was exchanged with ions of interest and, after washing, the gel was calcined at 723 K in air. The crystallographic features of Gd and Ho co-doped cerium oxide were investigated around the desired operating temperatures of IT-SOFCs, i.e. 573 ≤ T ≤ 1023 K. We find that the crystal structure is a stable fluorite structure with the space group Fm\overline{3}m in the entire temperature range. In addition, the trend in lattice parameters shows that there is a monotonic increase with increasing temperature.

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Żelazny, Henryk. "Assessment of the possibility of profiting from solar energy through the use of walls with external sheet metal cladding." E3S Web of Conferences 45 (2018): 00105. http://dx.doi.org/10.1051/e3sconf/20184500105.

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The possibility of profiting from solar radiation through external walls was studied for an experimental, windowless livestock building. Temperature measurements on the wall surfaces were taken during winter, in two measuring series. On the first day, the average sol-air temperature on the outer surface of the east-facing wall was 7.4 °C and was even up to 2.2 °C lower than temperature of the outdoor air which was 9.6 °C. With the averaged temperature of inner surface of the wall reaching 21.3 °C, heat transfer form the outside into the building was impossible. An identical tendency in temperature distribution on surfaces was noticed on the west-facing wall. In the second measuring cycle, the sun temperature on external wall surfaces increased significantly — 13.3 °C on the eastern side, and 14.1 °C on the western side. They were noticeably higher than the outdoor air temperature which was 9.1 °C. However, the high indoor surface temperatures on the eastern and western walls — 21.2 °C and 21.0 °C respectively, proved that in this case too, the transfer of heat generated by the sun’s radiation into the building was impossible. The tests results imply that we should exclude reheating the building with the heat from sun heat external walls during winter. However, a similar assessment including more measuring series and several objects, could be also be performed during interim seasons.

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Thompson, S. P., A. Herlihy, C. A. Murray, A. R. Baker, S. J. Day, A. J. Smith, and T. Snow. "Amorphous Mg–Fe silicates from microwave-dried sol–gels." Astronomy & Astrophysics 624 (April 2019): A136. http://dx.doi.org/10.1051/0004-6361/201834691.

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Context. Laboratory analogues can provide physical constraints to the interpretation of astronomical observations of cosmic dust but clearly do not experience the same formation conditions. To distinguish between properties intrinsic to the material and properties imprinted by their means of formation requires extensive characterisation. Aims. Sol–gel methods can produce amorphous silicates with potentially high reproducibility, but often require long drying times (24+ h) at elevated temperatures in air, controlled atmosphere, or vacuum. We investigate the possibility that microwave drying can be used to form amorphous silicate on a timescale of ∼10 min and characterise their structural and spectroscopic properties relative to silicates produced by other drying methods. Methods. Microwave-dried amorphous MgSiO3, Fe0.1Mg0.9SiO3 and Mg2SiO4 are characterised using X-ray powder diffraction, total X-ray scattering, small angle X-ray scattering and mid-IR FTIR spectroscopy, and compared to samples produced from the same gels but dried in-air and under vacuum. The development of crystalline structure in the microwave-dried silicates via thermal annealing up to 999°C is also investigated using in situ X-ray powder diffraction. Results. At the inter-atomic level the silicate structures are largely independent of drying method, however larger-scale structured domains, ranging from a ∼few × 10 Å to ∼100’s Å in size, are observed. These are ordered as mass fractals with discernible variation caused by the drying processes. The mid-IR 10 μm band profile is also found to be influenced by the drying process, likely due to the way removal of water and bonded OH influences the distribution of tetrahedral species. However, microwave drying also allows Fe to be easily incorporated into the silicate structure. In situ annealing shows that for amorphous MgSiO3 crystalline forsterite, enstatite and cristobalite are high temperature phases, while for Mg2SiO4 forsterite crystallises at lower temperatures followed by cristobalite at high temperature. For Fe0.1Mg0.9SiO3 the crystallisation temperature is significantly increased and only forsterite is observed. Crystalline SiO2 may be diagnostic of Mg-rich, Fe-poor grain mineralogies. The results are discussed in relation to the different thermal conditions required for dust to crystallise within protoplanetary disk lifetimes. Conclusions. Sol–gel microwave drying provides a fast and easy method of producing amorphous Mg- and Fe,Mg-silicates of both pyroxene and olivine compositions. Their structure and spectroscopic characteristics although similar to silicates produced using other drying methods, exhibit subtle variations which are particularly manifest spectroscopically in the mid-IR, and structurally over medium- and long-range length scales.

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Deng, Li Juan, Yu Rong Zhang, and Wei Li Liu. "The Effects of Li-Site Substitution with Co on the Electrochemical Performance of LiMnPO₄/C." Advanced Materials Research 512-515 (May 2012): 1009–13. http://dx.doi.org/10.4028/www.scientific.net/amr.512-515.1009.

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Li(1-2x)CoxMnPO4/C composite cathode materials for lithium ion battery are synthesized by sol-gel method with following heat-treatment in the air. Environment scanning electron microscopy measurements show that the particles are irregular and inhomogeneous, and that particle sizes slightly enlarge with the elevation of sintering temperatures. Powder X-ray diffraction analysis indicates that the samples are olivine-structured. Electrochemical tests indicate that the optimal sintering temperature registers 400 °C, and that the cyclic ability of LiMnPO4is greatly improved by doping Co2+. When tested at 0.02 C rate between 2.8 and 4.4 V, the initial discharge capacity of the sample with initial composition of x=0.07 sintered at 400 °C reaches 112.2 mAh/g , after 70 cycles, the capacities remain 58.8mAh/g.

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Aldbea, Ftema W., Noor Bahyah Ibrahim, Mustafa Hj Abdullah, and Ramadan E. Shaiboub. "Effect of Annealing temperature on the Structural and Magnetic Properties of Tb_xY_3-xFe₅O₁₂(x = 0.0, 1.0, 2.0) Thin Films Prepared by Sol-Gel Process." Advanced Materials Research 501 (April 2012): 236–41. http://dx.doi.org/10.4028/www.scientific.net/amr.501.236.

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Thin films nanoparticles TbxY3-xFe5O12 (x=0.0, 1.0, 2.0) were prepared by the sol-gel process followed by annealing process at various annealing temperatures of 700° C, 800° C and 900° C in air for 2 h. The results obtained from X-ray diffractometer (XRD) show that the films annealed below 900°C exhibit peaks of garnet mixed with small amounts of YFeO3 and Fe2O3. Pure garnet phase has been detected in the films annealed at 900°C. Before annealing the films show amorphous structures. The particles sizes measurement using the field emission scanning electron microscope (FE-SEM) showed that the particles sizes increased as the annealing temperature increased. The magnetic properties were measured at room temperature using the vibrating sample magnetometer (VSM). The saturation magnetization (Ms) of the films also increased with the annealing temperature. However, different behavior of coercivity (Hc) has been observed as the annealing temperature was increased.

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Lai, Chun Hung, Ching Fang Tseng, and Wen Yu Hsu. "Microstructure and Optical Properties of ZnO-Doped CeO₂ Thin Films Using Sol-Gel Method." Advanced Materials Research 486 (March 2012): 340–44. http://dx.doi.org/10.4028/www.scientific.net/amr.486.340.

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This paper describes microstructure and optical characteristics of ZnO-doped CeO2thin films were deposited by sol-gel method with various preheating and annealing temperatures. Particular attention will be paid to the effects of an annealing treatment in air ambient on the physical properties. The deposited films were characterized using X-ray diffraction. The surface morphologies of annealed film were examined by scanning electron microscopy. Optical properties of the ZnO-doped CeO2thin films were obtained by UV-visible recording spectrophotometer. The dependence of the optical properties and microstructure characteristics on thermal treatment was also investigated.

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Che Halin, Dewi Suriyani, Ibrahim Abu Talib, Abdul Razak Daud, and Muhammad Azmi Abd Hamid. "Effects of Annealing on the Properties of Copper Oxide Thin Films." Materials Science Forum 819 (June 2015): 189–92. http://dx.doi.org/10.4028/www.scientific.net/msf.819.189.

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Thin films of copper oxide were successively deposited on glass substrates by sol-gel like spin coating for 40 s and annealed in air at different temperatures (200-400°C). Precursor solutions were prepared by dissolving cupric chloride in methanol. Various stabilizers and additives were used to enhance the solubility of cupric chloride and to improve the adhesion between the films and the glass substrates. Glucopone was used as a surfactant to reduce the surface energy. The evolution of oxide coatings under thermal treatment was studied by glancing incidence X-ray diffraction and scanning electron microscopy. Annealing the films in air at 300°C converts the films to CuO. The general appearances of the films were uniform and brownish in color.

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35

Quan, Ngo Duc, Tran Quoc Toan, Vu Ngoc Hung, and Minh-Duc Nguyen. "Influence of Crystallization Temperature on Structural, Ferroelectric, and Ferromagnetic Properties of Lead-Free Bi0.5(Na0.8K0.2)0.5TiO3 Multiferroic Films." Advances in Materials Science and Engineering 2019 (January 9, 2019): 1–8. http://dx.doi.org/10.1155/2019/8976385.

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Lead-free Bi0.5(Na0.8K0.2)0.5TiO3 (abbreviated as BNKT) films have been synthesized via a sol-gel technique on Pt/Ti/SiO2/Si substrates, and the dependence of the physical properties in BNKT films were investigated as a function of the crystallization temperature. The BNKT films were annealed at different temperatures (600, 650, 700, and 750°C) for 60 min in the air. The results of this study showed that the optimal crystallization temperature is 700°C. At this, the BNKT films exhibited a single perovskite phase structure and high-dense surface. Besides, the remanent (Pr) and maximum (Pm) polarization reached their highest values of 9.2 µC/cm2 and 30.6 µC/cm2, respectively. All the films showed a weak ferromagnetic behavior with the maximum saturated magnetization (Ms) of 2.1 emu/cm3. These values are equivalent to the highest Pr and Pm values in previous reports on lead-free films.

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Dediu, Violeta, Viorica Musat, Bogdan Jurca, and Nicolae Ionut Cristea. "Thermal Decomposition of Some Sol-Gel Precursors for Mesoporous TiO2-Based Thin Films for Chemorezistive Environmental Sensors." Revista de Chimie 68, no. 8 (September 15, 2017): 1703–7. http://dx.doi.org/10.37358/rc.17.8.5748.

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This paper presents a comparative study on the thermal decomposition in air and FTIR analyses of complex sol-gel precursors used for the deposition of three titania based mesoporous thin films: TiO2, Nb-doped TiO2 and carbon nanotubes (MWCNT)-doped TiO2. The effect of doping with Nb or adding MWCNT on the thermal decomposition of titanium isopropoxide-based precursor and crystallization of TiO2 was investigated through thermogravimetric analysis (TGA), differential thermal analysis (DTA), and Fourier Transform Infrared (FTIR) data. TG-DTA results showed two main exothermic peaks were observed in all samples for the temperature range 280-300 oC and 429-444 oC, corresponding to isopropoxide oxidative decomposition and anatase crystallization. In case of Nb doped TiO2 an oxidative decomposition of Nb ethoxide appears at 198 �C. The acidified MWCNT are thermally stable up to 500�C. Doping TiO2 causes peaks shift to higher temperatures. Also, the effect of heating rate on thermal decomposition for precursors was studied. FTIR analyses were conducted on precursor systems thermally treated at different temperature to track the chemical transformations during the films formation.

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Ibrahim, Siti Aida, and Muhamad Nazim Ahmid. "Influence of Calcination Temperature towards Fe-TiO₂ for Visible-Driven Photocatalyst." Materials Science Forum 888 (March 2017): 435–40. http://dx.doi.org/10.4028/www.scientific.net/msf.888.435.

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TiO2 is one of the most promising photocatalysts that is widely used for environmental clean-up due to its ability to degrade organic pollutants in air or water. The purpose of this study is to enhance the photocatalytic activity of TiO2 by absorbing energy in visible light region in order to degrade pollutants. In this study, the nanostructured Fe-TiO2 was successfully synthesised via a combined method of sol-gel and calcination process. The calcination temperatures used varied from 400 to 800 °C. The as-prepared samples were characterized by X-ray diffraction (XRD), FESEM and UV-Vis spectroscopy (UV-Vis). XRD results show that the phases of TiO2 are dependent on calcination temperature. It is found that both TiO2 and Fe-TiO2 phases were transformed from anatase to rutile as the temperatures were increased. FESEM images revealed that the particle size was agglomerated and the average grain size was about 54 to 66 nm. UV-Vis analysis indicated that the incorporation of Fe and varied calcination temperature may affect the optical properties as the absorption profile was shifted from 445 nm to 585 nm. Thus, this results show that Fe-TiO2 is a highly potential photocatalyst to degrade pollutants under visible light irradiation.

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38

Ehara, Takashi, Kohei Sasaki, Marina Abe, and Takayoshi Nakanishi. "Preparation of Copper-Doped Nickel Oxide Thin Films by Sol-Gel Method Using Nickel and Copper Acetate." Materials Science Forum 909 (November 2017): 213–18. http://dx.doi.org/10.4028/www.scientific.net/msf.909.213.

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We have prepared nondoped and Cu-doped NiO thin films by sol-gel method on SiO2 substrate using nickel acetate and copper acetate as precursors. Thin films of NiO were formed by thermal annealing of gel films at 500 - 900°C for 10 h in air. X-ray diffraction (XRD) peaks of NiO have been observed at higher annealing temperature than 500°C, and intensity of the peaks increased with annealing temperature until 800°C. On the other hand, the dependency of XRD signal intensity on annealing temperature becomes less significant by Cu-doping. Nondoped NiO films show high transparency at lower annealing temperatures than 800°C. The result means that the film with high crystalline volume ratio is not consistent with the films with high transparency. Cu-doping decreases the transmittance of the films with low crystalline volume ratio. It is considered that the doped Cu atoms exist in amorphous fraction make the transmittance lower. Conductivity of the films is increased with Cu-doping only in the films annealed at 500 - 700°C. The highest conductivity obtained in the Cu-doped film is around 10-6 W-1cm-1 at 600°C. On the other hand, the Cu-doped films show similar conductivity to nondoped films at high annealing temperature, 800 or 900°C.

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Zachernyuk, Alexander B., Boris A. Zachernyuk, Ekaterina N. Solovyova, Vladimir I. Nedelkin, Lyubov A. Korneeva, and Sergey G. Bezryadin. "New approach to the formation of organo-inorganic borosyloxane polymer structures." Butlerov Communications 57, no. 2 (February 28, 2019): 35–40. http://dx.doi.org/10.37952/roi-jbc-01/19-57-2-35.

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Using sol-gel methods, new synthetic approaches to the preparation of boron-containing organic-inorganic hybrid polymers based on boron oxide (boric anhydride), which is a part of many inorganic materials, have been developed. Previously, such methods were used to obtain amorphous silicate glasses and their use allows introducing various inorganic and organic modifiers into the matrix of silicon dioxide and other compounds at temperatures up to 120 °C. Within the framework of this work: a) the conditions for obtaining saturated solutions of boron oxide in organic solvents were found and it was found that boric anhydride is most completely dissolved in triethyl orthoformiate (approximately 25%) at 110-110 °C retaining its structure; b) by the condensation of boric acid with 1,3-dichlorotetraphenyl disiloxane, functional borcyclosiloxanes were synthesized to further modify boron oxide. The reaction conditions, spectral and thermal characteristics of condensation products were investigated. It is shown the increasing in the synthesis time to 15-18 h, a bicyclic borsiloxane is formed; c) homophasic modification of boric anhydride with monofunctional cyclic borsiloxanes was carried out and it was shown that the formation of Si-O-B bonds at 110-120 °C occurs due to the use of anhydrous sol-gel process. Transparent films are obtained from modified boric anhydride solutions deposited on glass and stainless steel, followed by curing at a temperature of 160-280 °C, that are not subjected to hydrolysis under the action of air moisture and are stable in air up to 600 °C. As a result of the work, the possibility of obtaining a borsiloxane type polymeric structures having an inorganic molecular skeleton modified with organosilicon compounds has been investigated.

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Vishwas, M., K. Narasimha Rao, and Ashok M. Raichur. "Fabrication and Characterization of ZnFe₂O₄ Thin Film Based Metal-Insulator-Semiconductor Capacitors." International Letters of Chemistry, Physics and Astronomy 50 (May 2015): 151–58. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.50.151.

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Thin films of zinc ferrite (ZnFe2O4) were deposited on glass, quartz and p-silicon (100) substrates by the sol-gel method. The structural properties of the films were studied using x-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The XRD data show the film having a spinel structure and the crystalline phase exists after annealing at 500°C for 2 h in air. The SEM and AFM images show the nanocrystalline nature of the films. The optical transmittance decreased with increase of annealing temperature. The optical band gap energy was estimated at different annealing temperatures and found to be 2.71 eV after annealing at 400°C. The metal-insulator-semiconductor (MIS) capacitors were fabricated using ZnFe2O4 films on p-silicon (100) substrates. The capacitance-voltage (C-V), dissipation-voltage (D-V) and current-voltage (I-V) characteristics were studied. The dependence of dielectric constant on annealing temperature and signal frequency was analyzed. The variation of current density and resistivity of the ZnFe2O4 films with annealing temperature was also explored.

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Yamaguchi, Yuki, Tohru Kineri, Masakatsu Fujimoto, Hideo Mae, Atsuo Yasumori, and Keishi Nishio. "Investigation of Electrical Hydrogen Detection Properties of Pt/WO₃ Thin Films Prepared by Sol-Gel Method." Key Engineering Materials 485 (July 2011): 271–74. http://dx.doi.org/10.4028/www.scientific.net/kem.485.271.

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Platinum (Pt)nanoparticle-dispersed tungsten trioxide (WO3) thin film is a gasochromic material that changes color from transparent to blue in an H2 gas atmosphere. The electrical conductivity of Pt-nanoparticle-dispersed WO3 is dependent on inserted protons and electrons, though the material is insulator in air, because these electrons and protons work as electrical carriers in WO3. In this study, Pt-nanoparticle-dispersed WO3 thin films were prepared using the sol-gel process, and the optical and electrical properties were evaluated in an atmosphere with or without H2 gas. Pt/WO3 thin films prepared at 400°C showed the largest change in electrical conductivity when exposed to 1% H2 gas compared with thin films prepared at other temperatures. The electrical conductivity of the film was dependent on an H2 gas concentration in the range from 100 ppm to 1%. Pt/WO3 thin films prepared by the sol-gel process are expected to be used for H2 gas sensor devices due to the linear relationship between the electrical conductivity and H2 gas concentration.

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WEI, LI, BO WANG, DAPENG LIU, LAIN-JONG LI, YANHUI YANG, and YUAN CHEN. "IN SITU FORMATION OF COBALT NANOCLUSTERS IN SOL–GEL SILICA FILMS FOR SINGLE-WALLED CARBON NANOTUBE GROWTH." Nano 04, no. 02 (April 2009): 99–106. http://dx.doi.org/10.1142/s1793292009001563.

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A facile method was developed for in situ formation of Co nanoclusters in sol–gel silica thin films spin-coated on Si wafers. The size and density of Co nanoclusters can be controlled by spin-coating speeds, annealing methods, reduction temperatures under H 2, and metal precursor concentrations in tetraethylorthosilicate solutions. The optimized preparation condition, spin-coating speed of 9000 rpm, annealing at 500°C in air followed by reduction at 800°C in H 2, resulted in silica films as thin as 60 nm and Co nanoclusters with a mean diameter of 1.5 nm. Morphological and chemical characteristics of thin films and nanoclusters were studied by atomic force microscopy and X-ray photoelectron spectroscopy, respectively. Subsequently, these Co nanoclusters were successfully used to grow SWCNTs by CO decomposition. Film containing Co monometallic clusters produced SWCNTs of 1.3 nm in diameter, whereas film having Co/Mo bimetallic clusters produced SWCNTs of 0.9 nm. This sol–gel approach allowed not only easy catalyst patterning on a thin film but also a fine-tuning of SWCNT properties, e.g., diameter.

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Sopyan, Iis, Natasha Ahmad Nawawi, and Qasim Hussain Shah. "Dense Manganese Doped Biphasic Calcium Phosphate for Load Bearing Bone Implants." Advanced Materials Research 93-94 (January 2010): 393–96. http://dx.doi.org/10.4028/www.scientific.net/amr.93-94.393.

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Dense pure biphasic calcium phosphate (BCP) and Mn-doped BCP ceramics were fabricated via uniaxial pressing using the sol-gel derived powders. The compacted discs were sintered in air atmosphere with temperatures ranging from 1000 °C to 1400 °C. All powders have been proved to show HA and β-TCP phases only. Manganese doping improves the densification in the BCP structure as the relative density increased with Mn doping and also sintering temperature. Considerable grain growth has been observed at 1300 °C for Mn-doped BCP samples compared to the pure BCP. 15 mol% Mn showed the maximum hardness value of 6.66 GPa at 1400 °C compared to pure BCP of only 2.89 GPa. Similarly, the Mn-doped BCP has superior fracture toughness where it attained maximum values of 1.05 MPam1/2 at 1400 °C compared to 0.72 MPam1/2 at 1300 °C of pure BCP. In a nutshell, Mn doping has successfully brought improvement in the mechanical properties of the BCP.

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Lee, Jae Seol, Hyeon Taek Son, and Toyohiko Yano. "Formation of ZrO₂-Al₂O₃ Coating Layers on SiC Fiber by Dip-Coating Process." Key Engineering Materials 368-372 (February 2008): 1386–88. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.1386.

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The layers of ZrO2-Al2O3 were coated on the surface of SiC fibers (Tyranno SA fiber) by dip-coating process. The citric acid-ethylene glycol solution containing Al and Zr ions was polymerized at 150oC to obtain a polymerized complex precursor. The 2D-woven SiC Tyranno SA fibers were dipped into this precursor few times. Heat treatment for coated fiber was conducted at 800-1200oC for 1 h in air. Thin film of mixed zirconium/aluminum oxides on SiC fibers were successfully elaborated using the sol-gel process. The coated zirconium/aluminum oxides layer of SiC Tyranno SA fiber was about 200-1000 nm. The coated fibers were stable in an oxidizing environment even at high temperatures.

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Vo, Nguyen Xuan Phuong, Sung Pil Yoon, Suk Woo Nam, Jong Hee Han, Tae Hoon Lim, and Seong Ahn Hong. "Fabrication of an Anode-Supported Sofc with a Sol-Gel Coating Method for a Mixed-Gas Fuel Cell." Key Engineering Materials 277-279 (January 2005): 455–61. http://dx.doi.org/10.4028/www.scientific.net/kem.277-279.455.

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An anode-supported type solid oxide fuel cell (SOFC) is a promising structure resulting in a very high performance because it consists of a very thin electrolyte. In the preliminary stage, we have succeeded in the fabrication of Samaria-Doped Ceria (SDC) thin film on a porous Ni-Al substrate using a sol-gel coating technique. The thin electrolyte film binds the substrate well and a single cell made with the SDC thin-film electrolyte and porous LSM cathode exhibited a good performance in a mixed-gas condition, even at intermediate temperatures. The single cell, consisting of 20 µm thin SDC electrolytes, the porous Ni-Al anode substrate, and a LSM cathode, exhibited an open circuit voltage of 0.82V and a maximum power density of 0.31 W.cm-2 at 700°C with humidified methane and air mixtures. This cell also generated an open circuit voltage of about 1.1V and a maximum power density of 0.34 W.cm-2 at 600°C with humidified hydrogen as the fuel and air as the oxidant.

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Múzquiz-Ramos, E. M., Dora A. Cortés-Hernández, O. A. Herrera-Romero, and José C. Escobedo-Bocardo. "Preparation and Properties of CoFe₂O₄ Synthesized by the Modified Citrate-Gel Method." Materials Science Forum 644 (March 2010): 39–42. http://dx.doi.org/10.4028/www.scientific.net/msf.644.39.

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In this work, the synthesis of CoFe2O4 via sol-gel auto-combustion method, using iron nitrate, cobalt nitrate and citric acid, with subsequent heat treatment in air was studied. The effects of the molar ratio of the metal nitrates to citric acid and the heat treatment temperatures on the magnetic properties have been investigated. The X-ray diffraction patterns showed peaks consistent with cubic spinel-type structure. The average crystallite sizes were determined from the (311) peak of the diffraction pattern using Scherrer equation. Particle sizes in the range of 18-44 nm were obtained. The crystallite size increases with annealing temperature. Magnetic properties, such as saturation magnetization (Ms), remanent magnetization (Mr) and coercivity field (Hc) were measured at room temperature using a vibrating sample magnetometer. Saturation magnetization was found to increase with particle size, whereas coercivity was found to reduce exponentially as the particle size was increased, apart from the Hc of the sample treated at 300 °C. The present work shows that magnetic properties vary over a wide range by changing the synthesis conditions.

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47

Lamrani, Nouara, Ahcène Chaouchi, Jerôme Bernard, Brahim Itaalit, David Houivet, Jean Haussonne, and Mohamed Aliouat. "Influence of Li2Co3 and V2O5 combined additions on the sintering and dielectric properties of Ca0.5Sr0.5TiO3 ceramics prepared from powders synthesized by sol-gel method." Processing and Application of Ceramics 8, no. 2 (2014): 101–8. http://dx.doi.org/10.2298/pac1402101l.

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In this work, we have studied the influence of lithium carbonate (Li2CO3) associated with the vanadium oxide (V2O5) on sintering and dielectrics properties of Ca0.5Sr0.5TiO3 ceramic materials obtained from nanopowder synthesized by sol-gel method. The nanopowder was obtained by controlled mixing of titanium butoxide dissolved in butanol-2 and acetic acid with a saturated aqueous solution of calcium acetate and strontium carbonate and subsequent drying of the formed gel at 80 ?C and calcination at 1100?C. The synthesized nanopowder was mixed with different amount of additives, and then uniaxally pressed and sintered in air atmosphere at temperature determined by dilatomertic measurements. The pure Ca0.5Sr0.5TiO3 sample obtained by this process required a sintering temperature around 1500?C. The addition of Li2CO3 combined with V2O5 improved sinterability and caused a shift of dilatimeric shrinkage curve to much lower temperatures. Thus, dense ceramics (98% of theoretical density) were obtained at sintering temperature ? 1300?C. The effect of adding Li2CO3-V2O5 on the structure of ceramics and the dielectric properties is discussed and show that type I dielectric properties (linear variation of the permittivity) are conserved, but with an increase of dielectric loss.

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48

Kaminski, John E., Peter H. Dernoeden, and Michael A. Fidanza. "Environmental Monitoring and Exploratory Development of a Predictive Model for Dead Spot of Creeping Bentgrass." Plant Disease 91, no. 5 (May 2007): 565–73. http://dx.doi.org/10.1094/pdis-91-5-0565.

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Dead spot of creeping bentgrass is incited by Ophiosphaerella agrostis. The objectives of this 3-year field study were to: (i) elucidate environmental conditions associated with the expression of dead spot symptoms, (ii) develop a model to assist in predicting the appearance of dead spot symptoms and epidemics in creeping bentgrass, and (iii) elucidate the association between ascospore release and the appearance of new dead spot symptoms. Environmental parameters measured included relative humidity (RH), air (AT) and soil (ST) temperatures, solar irradiance (SOL), precipitation and irrigation (RAIN), and leaf wetness duration (LWD). Dead spot symptoms generally did not occur at temperatures (air or soil) below 15°C. Two descriptive models were developed that predicted the appearance of dead spot symptoms with an accuracy of 74 to 80%. Between 1 May and 31 October 2000 to 2002, the appearance of new dead spot infection centers was most accurately predicted (80%) by the single parameter of STMean ≥ 20°C. In years with severe levels of dead spot, the occurrence of major infection events was predicted on 37 of 40 days (93%). A combination of elevated air (ATMax ≥ 27°C) and soil (STMean ≥ 18°C) temperatures, low relative humidity (RHMean ≤ 80%), shortened periods of leaf wetness (LWD ≤ 14 h), and high levels of solar radiation (SOLMean ≥ 230 W m−2) were associated with the development of major dead spot epidemics. Ascospore discharge and the appearance of new infection centers occurred in a cyclic pattern that peaked about every 12 days. New infection centers appeared 3 to 10 days after the release of a large number of ascospores.

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BASANTAKUMAR SHARMA, H. "STRUCTURAL AND OPTICAL PROPERTIES OF SOL-GEL DERIVED BARIUM TITANATE THIN FILM." International Journal of Modern Physics B 21, no. 11 (April 30, 2007): 1837–49. http://dx.doi.org/10.1142/s0217979207037028.

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Ferroelectric barium titanate ( BaTiO 3) films have been prepared from barium acetate and titanium (IV) isopropoxide precursors by the sol-gel technique. The structural and optical properties of films annealed at different temperatures have been investigated. The as-fired films were found to be amorphous and crystallized to the tetragonal phase after annealing at 700°C for one hour in air. The lattice constants "a" and "c" were found to be 3.996 Å and 4.040 Å respectively. The X-ray density of the crystalline film was about 6.00 g · cm -3. The amorphous film showed very high transparency (~95%), which decreased slightly after crystallization (~90%). The band gap and the refractive index of the amorphous and crystalline films were estimated. The influences of porosity on the optical properties of films have also been investigated. The optical dispersion data are also analyzed in the light of the single oscillator model, and are discussed.

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Mo, Zhao Jun, Jing Lin, Ying Fan, Xing Hua Zhang, Yan Ming Xue, Chun Yong Liang, Hong Shui Wang, et al. "Morphology and Composition Controlled Synthesis of BN-Coated Aluminum Borate Nanowhiskers." Advanced Materials Research 509 (April 2012): 125–31. http://dx.doi.org/10.4028/www.scientific.net/amr.509.125.

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Large quantities of BN-coated aluminum borate (Al18B4O33) nanowhiskers with typical 20 - 50 nm in diameter and 0.5 - 2 m in length have been successfully synthesized by sol-gel and post-thermal-treatment methods. The dependence of morphology and structures on the synthetic process of the coated nanowhiskers has been investigated systematically. Al4B2O9 nanowhiskers were first prepared at a relative low temperature, and then converted into Al18B4O33 nanowhiskers at higher temperatures in the air due to their high-temperature instability. Besides Al18B4O33phase, Al5BO9 and B2O3 could also be generated in the process of transition. However, if a flow of NH3 gas was introduced during the post-thermal-treatment of Al4B2O9 nanowhiskers, the Al5BO9 and B2O3 phases disappeared and BN-coated Al18B4O33 nanowhiskers were finally obtained. Uniform BN layers were coated on the surface of the nanowhiskers by the interfacial reaction between NH3 and B2O3 vapor which was in-situ generated from the nanowhiskers. The NH3-introducing temperature has a significant effect on the morphology and composition of the nanowhiskers. The BN-coated Al18B4O33nanowhiskers are envisaged to become prime candidates as reinforcement in light metal matrix composites.

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Journal articles on the topic 'Sol-Air Temperatures'

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