• 한국세라믹학회지
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• 제45권9호
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• pp.561-566
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• 2008

Carbon fiber fabric-silicon carbide composites were fabricated by liquid silicon infiltration (LSI) process. The porous two-dimensional carbon fiber fabric performs were prepared by 13 plies of 2D-plain-weave fabric in a three laminating method, [0/90], [${\pm}45$], [$0/90/{\pm}45$] lay-up, respectively. Before laminating, a thin pyrolytic carbon (PyC) layer deposited on the surface of 2D-plain weave fabric sheets as interfacial layer with $C_3H_8$ and $N_2$ gas at $900^{\circ}C$. A densification of the preforms for $C_f-Si-SiC$ matrix composite was achieved according to the LSI process at $1650^{\circ}C$ for 30 min. in vacuum atmosphere. The bending strength of the each composite were measured and the microstructural consideration was performed by a FE-SEM.

• 한국세라믹학회지
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• 제45권4호
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• pp.238-244
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• 2008

Modeling and FEM analysis on Boron Nitride and/or Pyrolytic Carbon coating layers on SiC fibers under indentation contact loadings are investigated. Especially this study attempts to model the mechanical behavior of the SiC fibers with and without coatings. Tyranno S grade and Tyranno LoxM grade of SiC are selected for fiber and Boron Nitride and/or Pyrolytic Carbon as coating material. The modeling is performed by SiC fiber without coating layer, which includs single(BN or PyC) and double(BN-PyC or PyC-BN) coating layer. And then the analysis is performed by changing a type of coating layer, a type of fiber and coating sequence. In this study, the concepts of modeling and analysis techniques for optimum design of BN and PyC coating process on SiC fiber are shown. Results show that stresses are reduced when indentation contact loading applies on the material having lower elastic modulus.

• 한국세라믹학회지
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• 제44권3호
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• pp.169-174
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• 2007

TRISO coated fuel particle is one of the most important materials for hydrogen production using HTGR (high temperature gas cooled reactors). It is composed of three isotropic layers: inner pyrolytic carbon (IPyC), silicon carbide (SiC), outer pyrolytic carbon (OPyC) layers. In this study, TRISO coated fuel particle layers were deposited through CVD process in a horizontal hot wall deposition system. Also the computational simulations of input gas velocity, temperature profile and pressure in the reaction chamber were conducted with varying process variable (i.e temperature and input gas ratios). As deposition temperature increased, microstructure, chemical composition and growth behavior changed and deposition rate increased. The simulation showed that the change of reactant states affected growth rate at each position of the susceptor. The experimental results showed a close correlation with the simulation results.

• 환경위생공학
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• 제11권1호
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• pp.57-61
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• 1996

This study was to decompose carbon tetrachloride and CFC with pyrolytic incineration unit because of prohibition of their usage sooner or later. We have investigated heating value and temperature versus decomposing rate, removal of $Cl_2$ and dust in the flue gas, The results obtained were as follows; 1. In combustion condition to decompose $CCl_4$ heating value was 3,300Kcal/Kg, retention time was 2,0 sec. incinerator exit temperature was $950^{\circ}C$. 2.The removal of HCI and $Cl_2$ in flue gas used NaOH as reagent, then molar ratio o of $Na^+/Cl^-$ was 1.07. 3. NaCI of dust component was more than 90 %, 2 stage venturi scrubber was used to remove dust, then removal rate of dust was 99% over at L/G of $1.7Vm^3$

• Korean Chemical Engineering Research
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• 제56권6호
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• pp.798-803
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• 2018

Si을 리튬이온전지 음극활물질로 사용하기 위해 입도를 $0.5{\mu}m$ 보다 작은 크기로 제어하였고 표면에 탄소를 약 10 nm 두께로 코팅하였다. 그 위에 탄소섬유를 50~150 wt% 양으로 성장시키고 다시 한 번 탄소코팅을 진행하였다. 이렇게 만들어진 Si 합성물질은 전기전도성을 높이기 위한 공정으로 이종 금속을 혼합하였으며 수명 특성을 개선하기 위해 흑연과 복합화하였다. 실험 변수에 따른 재료들의 물리화학적 특성을 XRD, SEM 및 TEM을 사용하여 측정하였고 코인셀을 제조하여 전기화학적 특성을 평가하였다. Si/PC (Pyrolytic Carbon)/CNF (Carbon Nano Fiber)보다 Si/PC/CNF/PC가 전체적으로 Si 함량이 줄어 방전용량은 상대적으로 낮게 나타났지만 전지평가에서 중요한 수명특성에서는 좋은 결과를 보여주었다. 0.2 C rate에서 $1512mA\;h\;g^{-1}$의 초기 방전 용량과 78%의 초기 효율을 나타내었고 10 싸이클에서 94%의 용량 보존율을 보여주었다.

• 한국세라믹학회지
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• 제52권4호
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• pp.284-289
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• 2015

This study examined carbon layer coating on silicon carbide (SiC) fibers by utilizing solid-state and wet chemistry routes to confer toughness to the fiber-reinforced ceramic matrix composites, as an alternative to the conventional pyrolytic carbon (PyC) interphase layer. Electrophoretic deposition (EPD) of carbon black nanoparticles using both AC and DC current sources, and the vacuum infiltration of phenolic resin followed by pyrolysis were tested. Because of the use of a liquid phase, the vacuum infiltration resulted in more uniform and denser carbon coating than the EPD routes with solid carbon black particles. Thereafter, vacuum infiltration with controlled variation in phenolic resin concentration, as well as the iterations of infiltration steps, was improvised to produce a homogeneous carbon coating having a thickness of several hundred nanometers on the SiC fiber. Conclusively, it was demonstrated that the carbon coating on the SiC fiber could be achieved using a simpler method than the conventional chemical vapor deposition technique.

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2006년도 고분자리싸이클링 심포지엄
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• pp.15-32
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• 2006

Biomass had been attracted public attention as eco-friendly resource which not increases the greenhouse gas like carbon dioxide. In this study, it had been collected pyrolytic products such as bio-oil, char and pyrolytic gas from various biomass in a fluidized bed reactor which is one of the fast pyrolysis processes. To understand the characteristics of biomass pyrolysis, the variation of products yield and chemical composition was determined with various operating parameters like temperature, gas velocity($U_{0}/U_{mf}$) and bed height(L/D). In the optimum operating conditions, gas yield and water content was the lowest and concentration of guaiacols and syringols were the highest. The maximum yields of bio-oil was from 55% to 58% at $400^{\circ}C$.

• Carbon letters
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• 제4권1호
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• pp.36-39
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• 2003

Carbon and carbon-based materials are used in nuclear reactors and there has recently been growing interest to develop graphite and carbon based materials for high temperature nuclear and fusion reactors. Efforts are underway to develop high density carbon materials as well as amorphous isotropic carbon for the application in thermal reactors. There has been research on coated nuclear fuel for high temperature reactor and research and development on coated fuels are now focused on fuel particles with high endurance during normal lifetime of the reactor. Since graphite as a moderator as well as structural material in high temperature reactors is one of the most favored choices, it is now felt to develop high density isotropic graphite with suitable coating for safe application of carbon based materials even in oxidizing or water vapor environment. Carboncarbon composite materials compared to conventional graphite materials are now being looked into as the promising materials for the fusion reactor due their ability to have high thermal conductivity and high thermal shock resistance. This paper deals with the application of carbon materials on various nuclear reactors related issues and addresses the current need for focused research on novel carbon materials for future new generation nuclear reactors.

• 한국세라믹학회지
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• 제55권4호
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• pp.392-399
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• 2018

$C_f/SiC$ composites were prepared via a process combining chemical vapor infiltration (CVI) and precursor infiltration pyrolysis (PIP), wherein silicon carbide matrices were infiltrated into 2.5D carbon preforms. The obtained composites exhibited porosities of 20 vol % and achieved strengths of 244 MPa in air at room temperature and 423 MPa at $1300^{\circ}C$ under an Ar atmosphere. Carbon fiber pull-out was rarely observed in the fractured surfaces, although intermediate layers of pyrolytic carbon of 150 nm thickness were deposited between the fiber and matrix. Fatigue fracture was observed after 1380 cycles under 45 MPa stress at $1000^{\circ}C$. The fractured samples were analyzed by transmission electron microscopy to observe the distributed phases.

• 한국연초학회지
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• 제4권2호
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• pp.63-66
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• 1982

Coumarin was pyrolyzed at $500^{\circ}C$ in a stream of nitrogen. The pyrolyzates of coumarin were adsorbed on the activated charcoal and then eluded by carbon disulfide. The eluted pyrolyzates were identified using a gas chromatography/mass spectrometry. Benzene, toluene, phenylacetylene, styrene, benzofuran and naphthalene were detected from the pyrolyzates of coumarin on the basis of their mass spectra. The pyrolytic mechanism of coumarin was also discussed.