• Title/Summary/Keyword: Sol-gel preparation

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Preparation and Characterization of Organic-inorganic Hybrid Composite Film with Plate-shaped Alumina by Electrophoretic Deposition as a Function of Aging Time of Sol-Gel Binder

  • Kim, Doo Hwan;Park, Hee Jeong;Choi, Jinsub;Lim, Hyung Mi
    • Journal of the Korean Ceramic Society
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    • v.52 no.5
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    • pp.366-373
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    • 2015
  • Sol-gel binder was prepared by hydrolysis and condensation reaction using boehmite sol and methyltrimethoxysilane as a function of aging-time. The coating slurry was composed of a plate-shape alumina in the sol-gel binder for the EPD process, in which particles dispersed in the slurry were deposited on the electrode under an electric field due to the surface charge. We studied the effects of three parameters: the content of boehmite, the aging time, and the applied voltage, on the physical, thermal, and electrical properties of the hybrid composite films by EPD. The amount of boehmite was 10 ~ 20 wt% and the aging time was 0.5 ~ 72, with a fixed amount of plate-shape alumina of 10 wt%. The condition of applied voltage was 5 ~ 30 V with a distance of 2 cm between the electrode during the EPD process. We confirmed that a structure of hybrid composite films of well-ordered plate alumina was deposited on the substrate when the film was prepared using a sol-gel binder composed of 15 wt% boehmite with 1 hr aging time and EPD at 10 V. The process shows a weight loss of 7% at $500^{\circ}C$ in TGA and a breakdown voltage of 8 kV at $87{\mu}m$.

HTGR Nuclear Fuel Microsphere Preparation Using the Modified Sol-Gel Method (변형 Sol-Gel 방법을 이용한 고온가스로 핵연료 미세구입자 제조)

  • Jeong, Kyung-Chai;Kim, Yeon-Ku;Oh, Seung-Chul;Cho, Moon-Sung
    • Journal of the Korean Ceramic Society
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    • v.46 no.6
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    • pp.574-582
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    • 2009
  • $UO_2$ microsphere particles, core material of HTGR(High Temperature Gas Reactor) nuclear fuel, were prepared using by the GSP(Gel Supported Precipitation) method which is a modified-method of the wet sol-gel process. The spherical shape of initial liquid ADU droplets from the vibration nozzle system was continuously kept till the conversion to the final $UO_2$ microsphere. But the size of a final $UO_2$ microsphere was shrunken to about 25% of an initial ADU droplet size. Also, we found that the composition of dried-ADU gel particles was constituted of the very complicated phases, coexisted the U=O, C-H, N-H, N-O, and O-H functional groups by FT-IR. The important factors for obtain the no-crack $UO_2$ microsphere during the thermal treatment processes must perfectly wash out the remained-$NH_4NO_3$ within the ADU gel particle in washing process and the selections of an appropriate heating rate at a suitable gas atmosphere, during the calcining of ADU gel particles, the reducing of $UO_3$ particles, and the sintering of $UO_2$ particles, respectively.

Preparation of $Al_2O_3$.$2SiO_2$ glass by the sol-gel process (졸-겔법에 의한 $Al_2O_3$.$2SiO_2$ 유리의 제조)

  • Rhee, Jhun;Chi, Ung-Up;Jo, Dong-Soo
    • Journal of the Korean Ceramic Society
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    • v.20 no.1
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    • pp.3-12
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    • 1983
  • In the present study an attempt was made to synthesize the $Al_2O_3$.$2SiO_2$ glass in which atomic ratio is Al:Si=1:1 by sol-gel process. And at such a low temperature as 55$0^{\circ}C$ clear amorphous gel derived glass with Si-O-Al bonding was obtained. $Si(OC_2H_5)_4$ and $Al(NO_3)_3$.$9H_2O$ were used as the precursor and among the mutual solvents only n-butanol gave good results for the synthesis of the gel derived glass. Partial hydrolysis of TEOS with one-fold mol of $H_2O$ prior to the reaction with aluminum nitrate gave the better results., Total oxide content to the total reactants by weight was affective to the results.

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