Gradient multi-layer ceramic fiber aerogel: Fabrication, anti-oxidation and thermal insulation

Abstract

Aerogel is widely used in the field of thermal insulation. However, they exhibit brittleness and a dramatic increase in radiative heat transfer and effective thermal conductivity at high temperatures. Fiber composite aerogel achieved great progress, but the homogeneous structure hardly allowed heat convection, heat conduction, and heat radiation to be controlled simultaneously. In this paper, inspired by bamboo's multilayer and gradient structure, SiC fiber was prepared by electrostatic spinning, and TaSi2 and WSi2 particles were loaded on the fiber. Subsequently, SiC fiber was infiltrated by SiBCN ceramic precursors and then pyrolyzed to obtain gradient multilayer SiC/SiBCN ceramic fiber aerogel. The dense surface fiber reduced radiation heat transfer, and the porous structure of the aerogel decreased heat conduction and heat convection. The antioxidant particles improved the ceramic fiber aerogel's high-temperature oxidation resistance and thermal stability. The morphological structure, chemical composition, and thermal conductivity of ceramic fiber aerogel were characterized. The results showed that the gradient multilayer ceramic fiber aerogel had the comprehensive properties of ultra-low thermal conductivity, excellent infrared radiation shielding, and anti-oxidation performance. This study is expected to provide new ideas for constructing high-temperature thermal insulation ceramic aerogel.