• Title/Summary/Keyword: 초음파 분무 열분해법

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Synthesis of (${Ba_{1.3}}{Al_{12}}{O_{19}}$:$Mn^{2+}$) by Ultrasonic Spray Pyrolysis and Effect of Precursor Type on Morphology and Photoluminescence (초음파 분무 열분해법에 의한 바륨 헥사알루미네이트(${Ba_{1.3}}{Al_{12}}{O_{19}}$:$Mn^{2+}$) 제조 및 전구체 종류에 따른 형성과 발광 특성)

  • 김경화;강윤찬;김창해;박희동;최세영
    • Journal of the Korean Ceramic Society
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    • v.38 no.2
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    • pp.173-178
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    • 2001

  • 본 연구에서는 PDP용 녹색 형광체의 대안인 $Ba_{1.3}$A $l_{12}$ $O_{19}$:$Mn^{2+}$ 분말을 초음파 분무 열분해법으로 합성하였으며 활성제인 $Mn^{2+}$의 첨가량과 모체를 구성하는 바륨 및 알루미늄의 전구체 물질들의 조합을 변화시킴으로써 형광체 분말의 형태 및 발광특성을 조절하였다. 최적의 발광 휘도를 나타내는 $Mn^{2+}$의 농도는 0.25몰을 첨가하였을 때이며 녹색 발광 영역인 517nm에서 최대 발광 효율을 나타내었다. 바륨의 전구체 물질로는 초산염, 질산염, 염화물 및 수산화물을 사용하였으며 알루미늄 전구체 물질로는 질산염 및 염화물을 사용하였다. 전구체는 합성된 분말의 형상에 영향을 미치는데 구형을 유지하거나 혹은 뭉치거나 구형이 깨지는 등 전구체 조합에 따라 얻어지는 분말의 형태가 달라졌다. 합성된 형광체 분말들은 일반적인 고상 반응의 온도보다 낮은 열처리 온도인 140$0^{\circ}C$, 5시간 유지에서는 좋은 VUV 발광 특성을 가졌다. 또한 전구체의 조합은 형광체 발광 효율에도 영향을 미치는데 바륨과 알루미늄은 염화물을, 망간은 질산염을 사용하였을 때 가장 좋은 발광 휘도를 나타내었다.다.다.다.

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Gas Permeation Characteristics of Silica Membrane Prepared by Ultrasonic Spray Pyrolysis (초음파 분무 열분해법에 의해 합성한 실리카 막의 기체 투과 특성)

  • Lee Kew-Ho;Youn Min-Young;Park Sang-Jin;Lee Dong-Wook;Sea Bongkuk
    • Membrane Journal
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    • v.15 no.2
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    • pp.105-113
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    • 2005

  • Silica membranes were prepared on a porous metal sheet by ultrasonic spray pyrolysis method for gas separation at high temperatures. In order to improve the permselectivity, silica was deposited in the sol-gel derived $silica/\gamma-alumina$ intermediate layer by pyrolysis of tetraethyl orthosilicate (TEOS) at 873 K. The pyrolysis with forced cross flow through the porous wall of the support was very effective in plugging mesopores, Knudsen diffusion regime, that were left unplugged in the membranes. At permeation temperature of 523 K, the silica/alumina composite membrane showed $H_2/N_2$ and water/methanol selectivity as high as 17 and 16, respectively, by molecular sieve effect.

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Synthesis of Spherical Fine $PbTiO_3$ Particles by the Spray Pyrolysis Method Using Ultrasonic Vibrator (초음파 분무 열분해법에 의한 구형의 $PbTiO_3$ 미립자 제조)

  • 이서영;이동주;신건철
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.1 no.1
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    • pp.107-116
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    • 1991

  • Fine $PbTiO_3$ Particles were synthesized from the $Pb(NO_3)_2$and $TiO(NO_3)_2$ solution by the spray pyrolysis method using the ultrasonic vibrator as a mist generator. The obtained particles were characterized. The mechanisms of particle formation were discussed in comparison with those if other particles, such as $BaTiO_3$, $ZnO_2$, ZnO ....., in the same spray pyrolysis process.

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Preparation of Spherical $TiO_2$Powders by Spray Pyrolysis Using Ultrasonic Atomization Technique (초음파 분무 열분해법에 의한 구형 $TiO_2$ 미분말의 합성)

  • 이종흔;조형진;박순자
    • Journal of the Korean Ceramic Society
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    • v.28 no.10
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    • pp.831-837
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    • 1991

  • Spherical TiO2 particles are prepared from TiCl4 aqueous solution by the spray pyrolysis method using ultrasonic atomization technique. The formation mechanism of TiO2 particles from atomized droplets it studied by varying the concentration of the source solution, reaction temperature, and the solvent. spherical TiO2 powders with almost the same normalized particle size distribution can be made reproducibly by changing the concentration of the source solution, and their mean sizes are in the range of 0.2~1.4${\mu}{\textrm}{m}$.

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Preparation of Spherical (Zr, Sn)TiO4 Powders by Ultrasonic Spray Pyrolysis (초음파 분무 열분해법에 의한 $(Zr, SN)TiO_4$ 구형 미분말의 합성)

  • 조서용;이종흔;김명철;박순자
    • Journal of the Korean Ceramic Society
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    • v.31 no.5
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    • pp.465-470
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    • 1994

  • Fine, spherical (Zr, SN)TiO4 powders were prepared from the aqueous solution of metal chlorides by ultrasonic spray pyrolysis. Single phase (Zr, SN)TiO4 powders could be obtained above $700^{\circ}C$ (=temperature of the reactor) and all powders exhibited sizes in the range of 0.1 to 2.0 ${\mu}{\textrm}{m}$ and a narrow size distribution. The sintering properties of the prepared powders were better than those of the powders from solid-state reaction.

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