Study on Erosion Behavior and Microscopic Structure of Multi-directional Braided Carbon-carbon Composites

摘要

This paper makes use of ground small engine to take aluminum/no aluminum ablation researches on C/C throat lining;engines adopted with diameters are $220 and $330. A scanning electron microscope is used to observe the micro morphologies of inner surface of the ablated nozzle made of C/C materials. Evolution process of ablation structure is analyzed in combination of macro parameters. It is commonly found that there are carbon depositions after ablation, and the deposition under condition with aluminum is severer than that without aluminum. The deposition layer takes its shape in the late period of engine operation, which is caused by the decomposition of hydrocarbons and alkanes in oxidizing gases due to decrease of temperature and flow velocity. Through analysis on the experimental data, it is indicated that particle erosion exerts slight effect on ablation rate of throat insert of C/C materials on small ablation engine. Under condition either without or with aluminum, the filaments at the throat take the typical shape of tender tips of bamboo shoots, while the filaments in expansion section that is not burnt heavily are not sharply shaped, and no significant particle erosion morphology is observed.