Carbon Fiber Felt Reinforced TaC ‐ LaB 6 /Silicone‐Modified Phenolic Aerogel Composites: Lightweight, Low Shrinkage and Enhanced Ablation Resistance

ABSTRACT A carbon fiber felt was introduced as a 3D reinforcement skeleton. TaC‐LaB 6 nano‐ceramic fillers were added synergistically. A series of ceramizable aerogel composites were successfully prepared. The results show that the composites remain lightweight (density 0.305–0.436 g/cm 3 ). Their volume shrinkage after drying is as low as about 0.6%. The composites exhibit obvious anisotropy. The ceramic fillers significantly improve high‐temperature stability. As the ceramic filler content increases, the high‐temperature stability improves significantly. In air at 1000°C, the mass retention rate increases from 60.18% to 81.90%. Meanwhile, the linear ablation rate decreases from 0.072 to 0.041 mm/s. Overall, considering the comprehensive balance of low density, mechanical properties, and ablation resistance, the CSiPR‐3 sample (50% filler) exhibits the best overall performance. During ablation, TaC and LaB 6 undergo a series of reactions. They finally form a dense composite protective layer. This layer consists of Ta 2 O 5 , LaTaO 4 , and a borosilicate glass phase. It effectively blocks the erosion of heat flow and oxygen.