Papers by Keyword: Sol-Gel Process

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Authors: Anatoli Khodorov, M.J.M. Gomes
Abstract: Lanthanum modified lead zirconate titanate (PLZT) thin films were fabricated on indium doped tin oxide (ITO) - coated glass substrate by sol-gel method. The structure of the films was characterized with XRD and SEM. In the case of PLZT the dielectric function was modelled as a sum of Lorentzian oscillators and found by fitting the transmittance and reflectance spectra measured at normal incidence in the wavelength range of 220-2400 nm. The anomalous behaviour of dielectric function was observed below the absorption edge that was suggested to be due to formation of some defect states. The evolution of the absorption edge as well as dielectric function with film thickness was observed and discussed.
Authors: Torpong Sittiphan, Pattarapan Prasassarakich, Sirilux Poompradub
Abstract: In situ silica filling of styrene grafted natural rubber (ST-g-NR) was carried out by using sol-gel reaction of tetraethoxysilane (TEOS). The effects of concentration of catalyst and reaction temperature on the in situ silica content were investigated. ST-g-NR was synthesized via an emulsion polymerization using cumene hydroperoxide (CHPO) and tetraethylene pentamine (TEPA) as initiators. The synthesized ST-g-NR was characterized by a Fourier Transform Infrared Spectroscopy (FTIR) and Proton Nuclear Magnetic Resonance Spectroscopy (1H NMR). The content of in situ silica generated in ST-g-NR matrix was determined by Thermogravimetry Analysis (TGA). In situ silica up to 50 parts per hundred rubbers by weight (phr) was successfully filled in the ST-g-NR matrix. The silica content increased with the increase of n-hexylamine concentration. However, the effect of reaction temperature was insignificant to silica content.
Authors: Ying Li, Qiang Xu, Ling Dai
Abstract: In order to prepare ultrafine La3NbO7 powder, a potential material for thermal barrier coatings, the calcination process of La3NbO7 was studied in this paper.The precursor of La3NbO7 was synthesized by using a citric acid complex method. A calcination process had been systematically investigated. The reaction temperature was determined by differential scanning calorimetry (DSC). The phase composition of powders was characterized by X-ray diffraction (XRD), and the morphology was obtained by scanning electron microscope (SEM). The results revealed that the single-phase La3NbO7 powder could be successfully prepared while the calcination temperature exceeded 800°C and a better morphology could be maintained at 800°C for 4 hours. Considering all above, an optimum calcination scheme was adopted at 800°C for 4 hours. The as-prepared La3NbO7 powders had a grain size of about 50nm and an average particle size of about 300nm.
Authors: Giorgio de Angelis, Mauro Capone, Carlo Fedeli, Giuseppe A. Marzo, Mario Mariani, Elena Macerata, Marco Giola
Abstract: A novel method proposed by Korea Atomic Energy Research Institute has been applied to the treatment of chloride salt wastes coming from electrorefining of spent nuclear fuel, which allows to separate uranium from fission products. It is based on a matrix, SAP (SiO2-Al2O3-P2O5), synthesized by a conventional sol-gel process, able to stabilize the volatile salt wastes due to the formation of metalaluminosilicates, metalaluminophosphates and metalphosphates. With this method a higher disposal efficiency and a lower waste volume can be obtained. Eutectic melt LiCl-KCl (59-41 mol%) has been used to simulate the waste salt. The composite SAP has been prepared by using tetraethyl ortosilicate (TEOS), aluminum chloride (AlCl3.6H2O) and phosphoric acid (H3PO4) as sources of Si, Al, and P, respectively. All reagents were dissolved in EtOH/H2O and the mixture, tightly sealed, was placed in an electric oven at 70 C. After a gelling/ageing for 3 days, the transparent hydrogels were dried at 110 C for 3 days and then thermally treated at 600 C for 2 hours. The final product (SAP) was reacted with metal chlorides at increasing temperatures for 20 hours inside an Argon-atmosphere glove-box, after mixing them at a SAP/metal chloride mixing ratio of 2. The obtained products have been characterized by means of density measurements, scanning electron microscopy, thermal analysis, as well as by XRD, FTIR and Raman spectra. Financial support from the Nuclear Fission Safety Program of the European Union (project SACSESS, contract FP7-CP-2012-323282) is gratefully acknowledged.
Authors: I. Ruth Mangani, C.W. Park, Y.K. Yoon, S.H. Kim, J. Kim
Abstract: This work reports the effect of doping aluminium in the Li[Li(1/3-x/3)Crx-0.05M0.05Mn(2/3- 2x/3)]O2 (x= 0.2; M= Al), layered cathode material. The cathode material was prepared by citric acid assisted sol-gel process. The sample is characterized by TG/DTA, XRD and FESEM measurements. The Al- doped cathode has delivered an initial discharge capacity of 250 mAh/g with a current density of 0.12 mA/cm2.
Authors: Jai Hyun Kim, Kyung Shin Koh, Woong Kil Choo
Abstract: We have investigated the ferroelectric and electrical properties of PZT 40/60 films on the bottom La1/2Sr1/2CoO3(LSCO) electrode. The LSCO bottom electrode was sputtered on the SiO2/Si(100). As the annealing temperature of PZT capacitors on the LSCO is increased, the ferroelectric properties gradually increase with the annealing temperature up to 650°C. However, for the PZT capacitors annealed above 650°C, electrical measurement cannot be performed.
Authors: Ilaria Cacciotti, Giorgia Lehmann, Antonella Camaioni, Alessandra Bianco
Abstract: In this work, the sol-gel synthesis of AP40 bioactive glass system was reported. The obtained powder was fully characterised in terms of microstructure, composition and thermal behaviour by X-ray diffraction (XRD) measurements, Fourier transform infrared (FT-IR) spectroscopy, thermogravimetry and differential thermal analysis (TG-DTA). In vitro dissolution tests were performed in order to assess the degradation behaviour of sol-gel derived AP40 samples thermally treated at different temperatures. Finally, preliminary results on cytocompatibility are reported, based on bioresorption activity of human peripheral blood monocytes differentiated into osteoclasts on sintered disks.
Authors: Noboru Miyata, K. Fuke, Qi Chen, Kawashita Masakazu, Tadashi Kokubo, Takashi Nakamura
Authors: Yun Cang Li, Jian Yu Xiong, C.S. Wong, Peter D. Hodgson, Cui E Wen
Abstract: In the present study, titanium (Ti) samples were surface-modified by titania (TiO2), silica (SiO2) and hydroxyapatite (HA) coatings using a sol-gel process. The bioactivity of the film-coated Ti samples was investigated by cell attachment and morphology study using human osteoblast-like SaOS-2 cells. Results of the cell attachment indicated that the densities of cell attachment on the surfaces of Ti samples were significantly increased by film coatings; the density of cell attachment on HA film-coated surface was higher than those on TiO2 and SiO2 film-coated surfaces. Cell morphology study showed that the cells attached, spread and grew well on the three kinds of film-coated surfaces. It can be concluded that the three kinds of film coatings can bioactivate the surfaces of Ti samples effectively. Overall, Ti sample with HA film-coated surface exhibited the best bioactivity.
Authors: Noboru Miyata, K. Fuke, Q. Chen, Kawashita Masakazu, Tadashi Kokubo, Takashi Nakamura
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