Zero-ablative-recession nanoporous silicone composites with exceptional mechanical-thermal stability for reusable thermal protection system

Abstract

Cost-effective and durable thermal protection systems (TPS) is critical for reusable aerospace vehicles. Herein, we develop an affordable TPS based on nanoporous silicone composites (NSCs) with exceptional anti-ablation, thermal insulation, mechanical robustness, and reusability, which integrate high-temperature capability of non-ablative materials with functional effectiveness of ablative materials. The key innovation of NSCs is the robust and high-silica-content aerogel matrix, which exhibits superior thermal stability up to 1400 °C. Reinforced by low-density quartz fiber mats, the corresponding NSCs exhibit excellent properties including low densities of 0.4–0.8 g cm⁻³, high tensile strength of 13–42.9 MPa, and low room-temperature thermal conductivity of 0.033–0.07 W m⁻¹ K⁻¹. Moreover, the NSCs show excellent reusability as zero-recession ablative materials, retaining satisfactory mechanical and insulation properties after 10 tests at 1000 °C for 1000 s. Additionally, it also exhibits superior ablation-resistance with a linear ablation rate of 0.005 mm s⁻¹ at 1600 °C oxy-propane flow for 100 s. This powerful reusability and ablation-resistance are attributed to a continuous resilient ceramic layer generated from the silicone matrix via high-temperature organic–inorganic transformation, which could withstand extreme thermal atmospheres. The present materials merge the strengths of ablative and non-ablative materials, which should open new perspectives for a new generation of TPS.