Search / Korean Journal of Chemical Engineering
HWAHAK KONGHAK,
Vol.33, No.1, 1-8, 1995
탄소/탄소 복합재에 화학증착된 탄화규소의 증착속도 및 막의 특성에 미치는 증착조건의 영향
Effects of CVD Parameters on Deposition Rate and Thin Film Characteristics of the Chemical Vapour Deposited SiC on C/C Composites
탄소/탄소 복합재의 내산화성 향상을 위하여 화학기상증착법에 의한 탄화규소막을 형성할 때 증착시간, 증착온도, 총 유속, 반응기체(MTS:CH3SiCl3)의 몰분율 등 여러 가지 증착변수가 증착속도에 미치는 영향을 측정하였다. MTS/H2계에서 화학증착반응는 950℃이하의 온도구역에서는 주로 표면반응에 의해서 증착이 지배되고 그 이상의 온도에서는 주로 물질전달에 의해 지배되며 겉보기 활성화 에너지는 각각, 28.2Kcal/mole과 4.5Kcal/mole이였다. 증착된 증착층의 두께는 증착시간에 따라 일차식으로 증가하였으며, 화학 반응속도는 같은 반응조건에서는 시간에 따라 일정하였다. MTS의 몰분율이 증가함에 따라 증착속도가 역시 일차식으로 증가하였고, 탄소/탄소 복합재의 내산화성은 초기 산화개시 온도가 450℃에서 820℃로 개선되었다.
The effect of different deposition parameters such as deposition time, deposition temperature, total flow rate, mole fraction of reactant(MTS:CH3SiCl3)on the deposition rate of SiC on carbon/carbon composites was studied to obtain information on the improvement of oxidation resistance. The deposition process was found out to be activated process with surface reaction as the limiting step up to 950℃. The apparent activation energy obtained were about 282.2Kcal/mole, 4.5Kcal/mole, respectively. The film thickness and deposition rate increased linearly with the deposition time. The deposition rate was increased with increasing the mole fraction of CH3SiCl3, too. The improvement of the oxidation resistance of carbon/carbon composites can be achieved since oxidation initiation temperature, increased from 450℃ to 820℃ after SiC deposition.
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