Chemical vapor infiltration of activated carbon with tetramethylsilane

Chemical vapor infiltration of activated carbon with tetramethylsilane (TMS) at 200 hPa total pressure and a gas phase concentration of 15 (mol-)% TMS in nitrogen is studied. The influence of temperature on the infiltration process is discussed in detail. Up to 873 K, the infiltration is performed in the kinetically controlled regime resulting in high loadings up to around 42 (wt.-)%. The modified materials show high values for BET-surface and pore volume indicating a sufficient adoption of the infiltrated silicon layer to the surface morphology of the carbon substrates. Low oxidation resistance of the infiltrated material and EDX measurements give rise to the assumption that the infiltrated material is silicon. At higher infiltration temperatures above 873 K, particles are formed which have the shape of cylindrical nanostructures. EDX measurements reveal that silicon carbide is produced at these temperatures.