Densification behavior and ablation property of C/C-ZrC composites prepared by chemical liquid vapor deposition process at temperatures from 800 to 1100 °C

Chemical liquid vapor deposition (CLVD) process has got much attention because of its high efficiency and flexibility, but almost no reports are available in the fields of C/C-UHTCs preparation and the study of process parameters. In this work, CLVD-processed C/C-ZrC composites were fabricated at temperatures from 800 to 1100 °C, and the effects of temperature on the densification behavior and ablation property were discussed. Results displayed the mass gain, the deposition rate and the density uniformity were enhanced when the temperature increased from 800 to 900 °C, and thereafter they were reduced with the further arising temperature. Meanwhile, there were two different deposition modes due to the various temperatures. When the temperature was 900 °C, the sample possessed a good densification behavior, leading to a high density, great content of ZrC and homogenous distribution. These advantages promote a complete and dense ZrO₂ coating on the sample surface during ablation, which plays as an obstacle for oxidizing species diffusion and heat transfer. Thus, the specimen prepared at 900 °C exhibited an outstanding anti-ablation property. However, the densification behavior was deteriorated with the further increasing temperature. Especially, when the temperature increased to 1100 °C, the composites had a poor density, low content of ZrC and bad dispersion of ceramics. As a result, a loose and discontinuous oxide coating was formed on the ablation surface, and the oxidation and mechanical corrosion were severe, suggesting a poor ablation resistance.