Ultra-high temperature thermal insulated Ta4HfC5 porous ceramics with thermal stability and temperature resistance up to 2000 °C

High performance porous ceramics are the crucial thermal-insulation materials for the long-term and reliable service of hypersonic vehicles under extreme conditions. However, the insufficient thermal stability and poor temperature resistance of porous ceramics severely limit its application in extreme high temperature environment. Herein, the ultra-high temperature thermal insulated Ta 4 HfC 5 porous ceramic was prepared via preceramic polymer process combined with gel casting technology. The Ta 4 HfC 5 porous ceramic was composed of Ta 4 HfC 5 nanoparticles with the size of 100-120 nm and enjoyed a lightweight (0.81 g/cm 3 ),a low thermal conductivity (0.1 W/m·K), and superior compressive strength (1.12 MPa). Moreover, the Ta 4 HfC 5 porous ceramic maintained the hierarchical pores after heat treatment at 2000 °C for 1 h, indicating great application potential as the thermal insulation material in extreme conditions.