Morphology Measurement on Phenolic-Resin/Vitreous-Silica-Fabric Ablation Composites Modified with Tetraethoxysilicate and Silsesquioxanes

Abstract

This study focused on phenolic-resin/vitreous-silica-fiber (PR/VSF) ablation composites modified with silsesquioxane (SSO) and tetraethoxysilicate (TEOS). Three nanohybrids based on TEOS-SiO2(T-SiO2), octamethyl-SSO (Me-SSO) and phenyl-SSO (Ph-SSO) were prepared and employed to modify the PR/VSF ablation materials, T-SiO2/PR/VSF, Me-SSO /PR/VSF and Ph-SSO /PR/VSF. At a high temperature, the modified PR/VSiF coatings were melted under heats and then generated pre-ceramic bodies, avoiding damages from the heats for the parts of the body inside. To compare ablation properties of the three modifiers, the correlation of the material structures and ablation properties were discussed with ablation tests and morphology measured by SEM. As a result, the linear and the mass ablation of the three composites are in the order of T-SiO2/PR/VSF > Me-SSO/PR/VSF > Ph-SSO/PR/VSF. Therefore, the properties of Ph-SSO show that it is suitable and more effective as a modifier for ablation materials. In the temprature of about 2000oC, the results of ablative coating basically reached the expected technical indix.