Experimental investigation on ablation characteristics of silicon rubber insulator in different gas environments

The ablation experiment of silicon rubber insulator was carried out in gas environment and two-phase environment with Al₂O₃, and the influence of gas speed on charring ablation rate, carbon layer structure characteristics and the distribution regularity of main ingredient of the carbon layer was analyzed. The results show that the conduction path growth caused by intumescence of carbon layer and pyrolysis layer can't be neglected; the thickness of carbon layer tends to be reduced obviously along with gas speed increasing. the increase of internal pressure caused by blackage of pyrolysis gas path through carbon layer and thermo-stress may lead to destroy of carbon layer structure, the main ingredient C, O and Si of the carbon layer has the same distribution regularity along the thickness; under oxygen-rich environment the charring ablation rate is maximum and the process of ablation is different from the environment in the ablation test motor.