Chemical vapor deposition of pyrolytic carbon films on Si-Ti-C-O ceramic fibers

Pyrolytic carbon films were prepared by chemical vapor deposition on Si-Ti- C-O ceramic fiber, using argon or hydrogen as dilute gas with methane gas. The effects of argon or hydrogen gas on the deposition process were investi gated in terms of the temperatures and the duration of the incubation perio d preceding the formation of the film. When argon was used as the dilute ga s, carbon films were formed in the temperature range between 1350 K and 155 0 It, but when hydrogen was used, there was no deposition at temperatures b elow 1450 K. The activation energy for carbon film formation was 110 kJ/mol . The duration of the incubation period was about 1 ks. The incubation time might have been delayed because residual hydrogen from the hydrogen-cleani ng pretreatment hindered the film formation process and the surface conditi ons of the films had changed.