• 한국재료학회지
• /
• 제13권10호
• /
• pp.677-682
• /
• 2003

SiC nanowires were synthesized by carbothermal reduction using metal catalysts. Synthesized nanowires had mean diameters of 30∼50 nm and several $\mu\textrm{m}$ length. The kind of catalysts affects form of SiC nanowire because of difference of growth mechanisms. These differences were made by catalyst's physical property and relative activities to the source gas. Ni acted a conventional catalyst of VLS growth mechanism. But, Case of Fe, SiC nanowire was grown by stable VLS growth mechanism without relation of growth conditions. SiC nanowire was grown by two step growth model using Cr catalyst. Conversion ratios to the SiC nanowire were increased with growth conditions. Case of Cr, conversion ratio was about 45% that was higher than other catalyst used. This high conversion ratio was obtained by the addition VS growth to radial direction on the as-grown nanowires.

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