Thermally stable high-performance phenolic resin aerogels (PRAs) are of great interest for thermal insulation because of their light weight, fire retardancy and low thermal conductivity. However, the drawbacks of PRA synthesis, such as long processing time, inherent brittleness and significant shrinkage during drying, greatly restrict their wide applications. In this work, PRAs were synthesized at ambient pressure through a near-net shape manufacturing technique, where boron-containing thermosetting phenolic resin (BPR) was introduced into the conventional linear phenolic resin (LPR) to improve the pore characteristics, mechanical properties and thermal performances. Compared with the traditional LPR-synthesized aerogel, the processing time and the linear shrinkage rate during the drying of the PRAs could be significantly reduced, which was attributed to the enhanced rigidity and the unique bimodal pore size distribution. Furthermore, no catastrophic failure and almost no mechanical degradation were observed on the PRAs, even with a compressive strain of up to 60% at temperatures ranging from 25 to 200 °C, indicating low brittleness and excellent thermo-mechanical stability. The PRAs also showed outstanding fire retardancy. On the other hand, the PRAs with a density of 0.194 g/cm³ possessed a high Young’s modulus of 12.85 MPa and a low thermal conductivity of 0.038 W/(m·K).

Ultra-high-temperature materials (UHMs) are indispensable for extreme thermal environments (e.g., temperatures exceeding 2000 °C); however, their practical implementation remains severely constrained by demanding processing conditions, including extreme sintering temperatures, prolonged cycles, densification barriers and high equipment cost. In order to meet the low-cost and ablation-resistant requirements of aircraft nose cones, a facile organic–inorganic hybrid strategy is proposed to fabricate ZrB₂–HfC–SiC composites using a high-char-yield 1,2-dicyanobenzene (DCB) binder, enabling low-temperature moulding at merely 250 °C (2 h; 20 MPa). Upon high-temperature oxidative exposure, the DCB matrix undergoes in situ pyrolysis and synergistic co-sintering with the ceramic powders, producing a multi-layered, self-protective structural architecture. A comprehensive structure–temperature map correlating temperature-dependent phase evolution with flexural strength and thermal conductivity is established, thereby elucidating the underlying self-healing and ablation-resistance mechanisms. The hybrid material in this work exhibits excellent flexural strength, ablation resistance and thermal stability. This study successfully reconciles the long-standing contradiction between low-temperature processability and ultra-high-temperature (2600 °C) service durability, offering a scalable route for next-generation thermal protection systems.