Improving high heat flux ablation resistance of silicone rubber composites by laying low-areal-density carbon fiber fabrics

Abstract

To meet the thermal protection requirements under stress or high heat flux environments in advanced space vehicles, it is imperative to enhance the ablation resistance of flexible silicone rubber-based materials. In this study, low-areal-density carbon fiber fabric with distinctive mesh-like feature was introduced to build a high-strength char layer to improve the thermal protection capability. Under high heat flux (3.52 MW/m2), with the number of fabrics in the samples from 0 to 9, the compressive strength of the char layer reaches 9.400 MPa, developing by an impressive 134.65 %. In addition, the strong oxidation-resistant ceramization products converted from the silicone rubber matrix during ablation forms a skin-core structure with the fiber bundles, which conducive to prevent oxidative damage to the fabric. Further, the evolution of the char layer under different heat flux was revealed to assess the influence of fabric reinforcement on the ablation performance. In contrast to the composite without fabric (3.52M-0L), the fabric reinforced sample (3.52M-9L) with the best ablation resistance showed a decrease of 13.93 % in linear ablation rate and 30.43 % in mass ablation rate under the 3.52 MW/m2 heat flux. This study provides guidance for the design of flexible thermal protection materials with exceptional ablative resistance to withstand more severe operational environments.