Gradient and lightweight thermal protection systems enabled through solid–liquid phase transition with superior impact and ablation resistance

The extreme thermal conditions encountered during planetary reentry challenge the performance limits of conventional homogeneous thermal protection systems (TPS), motivating the exploration of advanced architectures, among which gradient architectures have emerged as a particularly promising approach. However, the controllable fabrication of gradient composites with high service reliability remains a critical challenge, necessitating the development of a new and robust strategy for constructing gradient thermal protection system (G-TPS). Here, we propose a pressure-assisted melt infiltration strategy to construct G-TPS. By exploiting the temperature-dependent solid–liquid phase transition of ceramic–resin mixture (CR), a dense thermal protection layer (TPL) is precisely formed on the fabric surface, while a lightweight phenolic aerogel is generated within the fabric, enabling seamless integration with TPL. Benefiting from the well-defined gradient architecture and robust interfacial bonding, the resulting composites maintain a low density (<0.5 g/cm 3 ) while delivering exceptional impact resistance and ablation resistance. Notably, the composites exhibit no surface damage after a 5 J drop-hammer impact and withstand five repeated oxy–acetylene torch tests at 1600 °C without failure. The G-TPS with its fabrication process provides a versatile design paradigm for TPS under extreme environments and shows strong potential for extension to other high-performance gradient composite systems.