• Title/Summary/Keyword: Sol-gel preparation

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Silica Glass Preparation by The Sol-Gel Process and The Effects of Glycerol as a DCCA (졸-겔법에 의한 실리카 유리의 제조와 DCCA로서의 Glycerol의 영향)

  • 이경희;이병하;이헌식;오부근
    • Journal of the Korean Ceramic Society
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    • v.25 no.5
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    • pp.479-487
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    • 1988
  • In this study we studied the function of Glycerol as a DCCA(Drying Control Chemical Additives) in the preparation of silica bulk glas through Sol-Gel method. We used TEOS(Tetra Ethyl Ortho Silicate) and maintained the mixing ratio of TEOS : H2O : EtOH : HCI as 1 : 4 : 4 : 0.0007(mol) and varied glycerol input quantity from 0.1vol% considering the ethnaol input quantity as 100vol%. We investigated the changes from Sol-Gel Synthetic solutions to the glass using DT-TG, FT-IR and other instruments. The results obtained from this experiment showed that the dried gels made from the synthetic solutions containing 0.1-1.0vol% of glycerol were easily heat-treated up to 85$0^{\circ}C$ so that transparant bulk silica glass was prepared.

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Studies on the Preparation of SiO2-TiO2-V2O5 Catalyst by SOL-GEL Method and its Application as a Simultaneous Removal of NOx and SOx from Stationary Sources (SOL-GEL법을 이용한 SiO2-TiO2-V2O5계 촉매들의 제조와 촉매상에서의 고정원 배가스 중 NOx 및 SOx의 동시제거에 관한 연구)

  • Bae, Seungju;Choung, Sukjin
    • Applied Chemistry for Engineering
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    • v.7 no.2
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    • pp.269-279
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    • 1996
  • The porous armophous catalysts, composed of $SiO_2-TiO_2-V_2O_5$ were prepared through SOL-GEL process by differing the preparation parameters. Selected the optimum SOL-GEL catalyst which has the best NO removal activity through the screening test, and repeated coating it on the cordierite monolith which is the freely through and inert. And examined the NOx, SOx simultaneous removal effect under S. C. R. condition. In addition to its characterization performances by the DTA, TGA, BET, $NH_3$ and NO TPD, ESCA, XRD etc.

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Preparation and Properties of Inorganic-organic Hybrid $Li^+$ Ion Conductor by Sol-gel Process

  • Nishio, Keishi;Miyazawa, Tsutomu;Watanabe, Yuichi;Tsuchiya, Toshio
    • The Korean Journal of Ceramics
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    • v.7 no.1
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    • pp.1-5
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    • 2001
  • Inorganic-organic hybrid Li$^+$ ion conductors were prepared by the sol-gel process. Tetramethyl orthosilicate (TMOS), polyethylene glycol 200 (PEG$_200$) and lithium bis (trifluoro-methylsulfony) imide were used as raw materials and $H_2O$ was used as a solvent. Hybrid Li$^+$ ion conductor prepared by the sol-gel process showed very high ion conductivities of log${\sigma}_R.T$(S/cm)=-3.73, log${\sigma}_60$(S/cm)=-3.00 at room temperature and $60^{\circ}C$, respectivery. Decomposition voltage was 3.1 V.

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Preparation and Characterization of Small Sized PZT Powders: A Sol-Gel Modified Approach

  • Choi, Kyu-Man;Lee, Hae-Chun
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.1 no.2
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    • pp.27-32
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    • 2008
  • A current research basically diverted towards an increase in the operational output with the minimization of the materials used, which ultimately scaled down the dimensions of ceramic electronic components. In this direction the nano-technology pave the revolutionary changes in particular the electronic industries. The applications of nano-sized particles or nano-sized materials are hence, playing a significant role for various purposes. The PZT(lead, zirconium, titanium) based ceramics which, are reported to be ferroelectric materials have their important applications in the areas of surface acoustic waves (SAW), filters, infrared detectors, actuators, ferroelectric random access memory, speakers, electronic switches etc. Moreover, these PZT materials possess the large electro mechanical coupling factor, large spontaneous polarization, low dielectric loss and low internal stress etc. Hence, keeping in view the unique properties of PZT piezoelectric ceramics we also tried to synthesize indigenously the small sized PZT ceramic powder in the laboratory by using the modified sol-gel approach. In this paper, propyl alcohol based sol-gel method was used for preparation of PZT piezoelectric ceramic. The powder obtained by this sol-gel process was calcined and sintering to reach a pyrochlore-free crystal phase. The characterization of synthesized material was carried out by the XRD analysis and the surface morphology was determined by high resolution scanning electron microscopy.

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EFFECT of PREPARATION METHODS and CONDITIONS of PRECURSORS on the PROPERTIES of $BATIO_3$ ALKOXIDE FILMS

  • N., Korobova;Soh, Dea-Wha
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.714-718
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    • 2003
  • Usually for the commercial preparation of barium titanate films or ceramics the reaction atmosphere must be preferably in air. However, normally air is not used because it contains carbon dioxide, which can easily react with barium to form the undesired product barium carbonate, leading to unwanted second-phase formation in the (mal stages of the process. In the present work a series of perovskite barium titanate films was prepared by the sol-gel method, using a metal alkoxide solutions in the electrophoretic deposition (EPD). The influence of several process parameters, like sintering temperature of sol preparation before EPD and heat-treatment temperature and non-oxidized atmosphere, on the film properties is described.

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Preparation of Ferroelectric PZT Thin Film by Sol-Gel Processing; (I) Synthesis of Stable PZT Sol Using Chelating Agent and Preparation of Its Thin Film (졸-겔법에 의한 강유전성 PZT 박막의 제조;(I) 킬레이팅 에이전트를 이용한 안정화 PZT 졸의 합성 및 박막의 제조)

  • Kim, Byong-Ho;Hong, Kwon;Cho, Hong-Yeon
    • Journal of the Korean Ceramic Society
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    • v.31 no.7
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    • pp.804-812
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    • 1994
  • Stable PZT coating sol was prepared using chelating agent, ethylacetoacetate(EAcAc) by sol-gel processing under ambient atmosphere. Through FT-IR spectrum analysis on solution of each reaction step, formation of metal complex was confirmed and prepared PZT sol was stable over several months. Through TG-DTA, XRD, FT-IR spetrum analysis of PZT gel powder, it was understood that the addition of EAcAc could reduce the transition temperature to ferroelectric phase, due to the increased homogeneity by matching the hydrolysis and condensation rates by chelation. Single perovskite phase was obtained by the heat-treatment at 54$0^{\circ}C$ for 30 min. The film was coated on ITO-coated glass substrate by dip coating method. After heat-treatment, PZT thin film had thickness in the range of 20~130 nm. The maximum dielectric constant of its thin film at room temperature and 1 kHz was 128.

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Preparation and Characteristics of PLT(28) Thin Film Using Sol-Gel Method (Sol-Gel 법을 이용한 PLT(28) 박막의 제작과 특성)

  • Kang Seong Jun;Joung Yang Hee;Yoo Jae-hung
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.9 no.7
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    • pp.1491-1496
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    • 2005
  • We fabricated the $Pb_{0.72}La_{0.28}TiO_3$ (PLT(28)) thin film successfully by using the sol-gel method and characterized it to evaluate its potential for being utilized as the capacitor dielectrics of ULSI DRAMs. In our sol-gel process, the acetates were used as the starting materials. Through the TGA-DTA analysis, we established the excellent fabrication conditions of the sol-gel method for the PLT(28) thin film. We obtained the dense and crack-free PLT(28) thin film of $100\%$ perovskite phase by drying at $350^{\circ}C$ after each coating and final annealing at $650^{\circ}C$. Electrical properties of PLT(28) thin film were measured through formation on the $Pt/Ti/SiO_2/Si$ substrate and its dielectric constant and leakage current density were measured as 936 and $1.1{\mu}A/cm^2$, respectively.