• 한국세라믹학회지
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• 제32권12호
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• pp.1417-1423
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• 1995

α/β sialon based composites containing silicon nitride whisker and silicon carbide platelet were fabricated by hot pressing. Effect of the reinforcing agents on the α to β phase transformation of the sialon as well as on the mechanical properties was investigated. Silicon nitride whisker and silicon carbide platelet promoted the phse transformation. TEM/EDS analysis revealed that the grain containing the whisker had 'core-rim' structure; core being high purity Si3N4 whisker and rim being β-sialon. Flexural strength of the composite decreased with the reinforcement addition which, on the other hand, improved fracture toughness of it. High temperature strength was measured at 1300℃ to be about 130 MPa lower than that measured at RT for the whisker reinforced composites.

• 한국세라믹학회지
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• 제40권9호
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• pp.832-836
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• 2003

Multi-layer ceramic composites were prepared by tape casting followed by hot pressing using silicon nitride layer with silicon nitride whiskers, silicon nitride layer with silicon carbide particles and boron nitride-alumina layer. The whiskers were aligned during the casting. As the whisker content of the silicon nitride layer was increased up to 10 wt％, the flexural strength of the multi-layer composite was increased. However, further increase of the whisker content in the layer resulted in a rapid decrease of the strength of the composite. The results suggest that the strength of multi-layer ceramic composite showing non-catastrophic failure behavior can be significantly improved by incorporating the aligned whiskers in the layers.

• 한국결정학회:학술대회논문집
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• 한국결정학회 2005년도 추계학술연구발표회 및 정기총회
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• pp.21-21
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• 2005

• 마이크로전자및패키징학회지
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• 제10권3호
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• pp.67-71
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• 2003

실리콘 주괴(ingot)에서 실리콘 웨이퍼를 제조할 때 사용되는 슬러리는 SiC 연마재와 절삭유를 포함한다. 실리콘 웨이퍼 제조 시 생긴 폐슬러지에서 SiC 연마재와 절삭유는 분리되어 재활용된다. 본 연구는 폐슬러지 Si 분말에 C분말을 혼합하여 SiC를 합성하는 것에 관한 것이다. 다양한 크기의 SiC 분말과 휘스커가 제조되었으며 기존의 휘스커의 크기보다 작은 나노미터 크기의 휘스커도 발생하였다. 일반적으로 휘스커는 금속 불순물을 첨가하여 제조되는데, 본 연구에서 나노미터 크기의 휘스커 발생은 폐슬러지에 첨가되어있는 미세한 크기의 금속불순물의 영향으로 판단된다.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2002년도 추계총회 및 연구발표회 초록집
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• pp.22.1-22
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• 2002

• 한국세라믹학회지
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• 제35권12호
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• pp.1329-1336
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• 1998

A twt -step carbothermal reduction scheme has been employed for the synthesis of SiC whiskers in an Ar or a H2 atmosphere via vapor-solid two-stage and vapor-liquid-solid growth mechanism respectively. It has been shown that the whisker growth proceed through the following reaction mechanism in an Ar at-mosphere : SiO2(S)+C(s)-SiO(v)+CO(v) SiO(v)3CO(v)=SiC(s)whisker+2CO2(v) 2C(s)+2CO2(v)=4CO(v) the third reaction appears to be the rate-controlling reaction since the overall reaction rates are dominated by the carbon which is participated in this reaction. The whisker growth proceeded through the following reaction mechaism in a H2 atmosphere : SiO2(s)+C(s)=SiO(v)+CO(v) 2C(s)+4H2(v)=2CH4(v) SiO(v)+2CH4(v)=SiC(s)whisker+CO(v)+4H2(v) The first reaction appears to be the rate-controlling reaction since the overall reaction rates are enhanced byincreasing the SiO vapor generation rate.

• 한국세라믹학회지
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• 제35권12호
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• pp.1336-1336
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• 1998

2단계 열탄소환원법으로 탄화규소 휘스커를 Ar과 H2분위기에서 기상-고상, 2단계, 기상-액상-고상 성장기구를 통해 각각 합성하였다. Ar분위기에서 탄화규소 휘스커는 다음과 같은 반응기구로 성장하였다. SiO2(S)+C(s)-SiO(v)+CO(v) SiO(v)3CO(v)=SiC(s)whisker+2CO2(v) 2C(s)+2CO2(v)=4CO(v) 이때 전체 반응속도는 세번째 반응에 참여하는 탄소에 의해 지배되었다. 따라서 이 반응이 휘스커 합성의 율속반응으로 판단되었다. 한편 H2 분위기에서 탄화규소 휘스커는 다음과 같은 반응기구로 성장하였다.SiO2(s)+C(s)=SiO(v)+CO(v) 2C(s)+4H2(v)=2CH4(v) SiO(v)+2CH4(v)=SiC(s)whisker+CO(v)+4H2(v) 이때 전체 반응속도는 SiO(v) 기체의발생 속도에 의해 지배되었다. 따라서 첫번째 반응이 휘스커 합성의 율속 반응인 것으로 판단되었다.

• 한국세라믹학회지
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• 제45권2호
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• pp.99-104
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• 2008

Zeta potential, sedimentation bulk density and rheology in the dispersion system have been studied in terms of solid loading (40-55 vol%), and types of additives. Ammonium polymethacrylate, glycerol, ethoxylated acetylenic diol, and polyvinyl alcohol have been used as the dispersant, cryo-protectant, surfactant, and binder, respectively. Sedimentation density greatly increased upon adding dispersant; the effect was more pronounced with ionic alumina suspension compared with covalent silicon carbide. With further addition of cryo-protectant and surfactant to dispersant, the sedimentation density increased somewhat. The suspension viscosity generally behaviored in an opposite manner to the sedimentation density, i.e., high sedimentation gave low high-shear viscosity, indicative of low order structure formation in the suspended particles. Shear rate rheology in shear rate of $2-300\;sec^{-1}$ showed a shear thinning and its onset began at similar shear rate (${\sim}100\;sce^{-1}$), regardless of solid loading.

• 한국세라믹학회지
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• 제35권12호
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• pp.1249-1256
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• 1998

${\beta}$-Silicon carbide(${\beta}$-SiC) whiskers could be synthesized by the carbothermal reduction of kaolin at tem-peratures between 1400 and 1500$^{\circ}C$. The whiskers were grown up to about 1150 of aspect ratio by VS mechanism (showing tapering tips) and to about 45 of that by VLS mechanism (showing round droplet tips) respectively. Hydrocarbon like methane in the reaction atmosphere promoted the formation of gaseous il-icon monoxide(SiO) from silicon dioxide(SiO2) and subsequently reacted with it to form whiskers. The for-mation of ${\beta}$-SiC whiskers increased with increasing carbon content(to 30 wt%) and reaction temperatures. The max. yield of ${\beta}$-SiC whiskers was 15% at 1500$^{\circ}C$ under 20%CH4/80%H2.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2003년도 춘계총회 및 연구발표회 초록집
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• pp.212.1-212
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• 2003