Scalable Fabrication of Lightweight, Thermally Insulating and Ablation-Resistant SiC/SiOC Hybrid Aerogel Composites Reinforced with High-Porosity Needle-Punched Quartz Fiber Felts

High-speed flight demands thermal protection materials combining lightweightness, high strength, efficient thermal insulation, and long-term oxidative ablation resistance. Herein, a ternary hybrid preceramic polymer system consisting of liquid polycarbosilane, polymethylhydrosiloxane, and 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane was designed through precise control of molecular structure and polymerization kinetics. The composite precursor sol was infiltrated into a high-porosity needle-punched quartz fiber felt via the resin transfer molding method, yielding an integrated thermal protection/insulation material with a bulk density below 0.40 g cm−3. The resulting composite exhibited a thermal conductivity as low as 0.042 W m−1 K−1 at room temperature and 0.082 W m−1 K−1 at 1000 °C, along with a compressive strength of 7.97 MPa at 10% strain, demonstrating outstanding mechanical performance. In ground-based arc-jet ablation tests (500 MJ m−2, 1500 s, ~1400 °C surface), LHRC-05 showed a back-face temperature rise of only 160.5 °C across a 25 mm thick specimen, with a linear ablation rate as low as 0.53 μm s−1, accompanied by a mass ablation rate of 0.021 g s−1 (near-zero volumetric recession). These results demonstrated that the fiber-reinforced SiC/SiOC aerogel composite integrated low density, high mechanical strength with efficient thermal insulation and excellent ablation resistance, making it a promising candidate for thermal protection systems in aerospace applications.