Design of the Thermal Restructured Carbon-Inorganic Composite Aerogel for Efficient Thermal Protection of Aero-Engines.

The heat insulation ability and thermal stability of thermal protection materials play extremely important role in the thermal protection of aero-engines under high temperature. Herein, we design the carbon-SiO2-Al2O3 (CSA) composite aerogel through thermochemical restructuring from the phenol-formaldehyde resin-SiO2-Al2O3 (PSA) composite aerogel. This thermochemical restructured aerogel not only shows better adhesion property under room temperature but also possesses higher thermal stability and desirable heat insulation ability under high temperature. Taking the PSA-0.5 composite aerogel as an example, the compressive strain-stress test unveils that it can be compressed by 66% without catastrophic collapse, which is beneficial for the adhesion with the metallic matrix. Meanwhile, the transmission electron microscopy and scanning electron microscopy images exhibit the unbroken three-dimensional structure for the CSA-0.5 composite aerogel, which confirmed the structural stability of the composite aerogel after thermochemical restructuring. The thermal cycle test indicates that the weight loss of the CSA-0.5 composite aerogel is only ca. 8%, firmly confirming its thermal stability. Importantly, the thermal conductivity of the CSA-0.5 composite aerogel ranges from 0.024 to 0.083 W m-1 K-1, indicating the superior performance of heat insulation. Moreover, the numerical simulation is carried out to validate the thermal protection effect of the CSA-0.5 composite aerogel as a thermal protection layer. Together with laminated cooling, it could enhance the surface cooling effectiveness of the metallic matrix to above 0.8. Briefly, this work paves a new pathway for efficient thermal protection materials of aero-engines via the rational design of the thermochemical restructured composite aerogel under the guidance of ANSYS numerical simulations.