• Title/Summary/Keyword: Carbothermal reduction

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Effect of the C/Si Molar Ratio on the Characteristics of β-SiC Powders Synthesized from TEOS and Phenol Resin (C/Si 몰 비가 TEOS와 페놀수지를 출발원료 사용하여 합성된 β-SiC 분말의 특성에 미치는 영향)

  • Youm, Mi-Rae;Park, Sang-Whan;Kim, Young-Wook
    • Journal of the Korean Ceramic Society
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    • v.50 no.1
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    • pp.31-36
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    • 2013

  • ${\beta}$-SiC powders were synthesized by a carbothermal reduction process using $SiO_2$-C precursors fabricated by a sol-gel process using phenol resin and TEOS as starting materials for carbon and Si sources, respectively. The C/Si molar ratio was selected as an important parameter for synthesizing SiC powders using a sol-gel process, and the effects of the C/Si molar ratio (1.4-3.0) on the particle size, particle size distribution, and yield of the synthesized ${\beta}$-SiC powders were investigated. It was found that (1) the particle size of the synthesized ${\beta}$-SiC powders decreased with an increase in the C/Si molar ratio in the $SiO_2$-C hybrid precursors, (2) the particle size distribution widened with an increase in the C/Si molar ratio, and (3) the yield of the ${\beta}$-SiC powder production increased with an increase in the C/Si molar ratio.

  • https://doi.org/10.4191/kcers.2013.50.1.31 인용 PDF KSCI

Synthesis of SiC Whiskers from Rice Hulls (생왕겨를 이용한 실리콘 카바이드 합성)

  • 길경선;김종학;고인용
    • Resources Recycling
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    • v.2 no.4
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    • pp.17-22
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    • 1993

  • SiC whiskers were synthesized from rice hulls and activated carbon by carbothermal reduction method. The effects of gases and various additives were studied. Carbothermal reduction to produce SiC whiskers was conducted at $1450^{\circ}C$ and the synthesized SiC whiskers were examined using SEM and XRD. The length of whiskers is increased with the increases of $H_2$concentration and total gas flows. The most favorable form of SiC whiskers couble be obtained in the following experimental conditins : Ar : $H_2$=300:45(ml/min), $SiO_2$(inrice hulls): $CaF_2$=1:0.5:0.5(mole ratio) and the addition of Ni flakes ($1{\times}1$mm).

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Synthesis and Characterization of Fiberous AlN by Electrospinning (전기방사에 의한 섬유상 질화알루미늄 합성 및 특성 평가)

  • Chun, Seung-Yeop;Hwang, Jin-Ah;Chu, Jae-Uk;Chun, Myoung-Pyo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.30 no.7
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    • pp.441-446
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    • 2017

  • Aluminum nitride fibers were synthesized by carbothermal reduction and nitridation of precursor fibers obtained by electrospinning. The starting materials used to synthesize the AlN fibers were $Al(NO_3)_3{\cdot}9H_2O$ and urea. Polyvinylpyrrolidone with increasing viscidity was used as the carbon source to obtain a composite solution. The mixed solution was drawn into a plastic syringe with a stainless steel needle, which was used as the spinneret and connected to a 20 kV power supply. A high voltage was supplied to the solution to facilitate the formation of a dense net of fibers on the collector. The precursor fibers were dried at $100^{\circ}C$ and then heated to $1,400^{\circ}C$ for 1 h in a microwave furnace under $N_2$ gas flow for the carbothermal reduction and nitridation. X-ray diffraction studies indicated that the synthesized fibers consisted of the AlN phase. Field emission scanning electron microscopy studies indicated that the diameter of the calcined fibers was approximately 100 nm.

  • https://doi.org/10.4313/JKEM.2017.30.7.441 인용 PDF KSCI