耐高温氧化铝基纳米棒气凝胶的制备与性能研究

A erogels have long been considered a highly promising material for aerospace thermal protection systems. Conventional alumina aerogels, composed primarily of nanoparticles, tend to undergo phase transformation to α-AI₂O₃ at temperatures exceeding 1 200 °C, accompanied by skeleton coarsening and pore collapse. In this study, we utilized inexpensive inorganic raw materials, boehmite micropowders, and leveraged the adsorption of anionic groups on the boehmite surface during the hydrothermal process to synthesize transparent boehmite nanorod sols. Subsequently, we employed the sol-gel method to interconnect these nanorods, successfully fabricating alumina-based nanorod aerogels with excellent thermal stability. The study investigated the microstructural evolution of these aerogels under high-temperature conditions and explored various factors influencing their thermal stability. The experimental results demonstrated that the synthesized aerogels exhibit outstanding comprehensive performance, including excellent heat resistance (withstand temperatures up to 1 400 °C), ultra-low thermal conductivity (0.016 80-0.025 36 W · m^-1 · K^-1), and low density (0.090 9-0.097 5 g · cm^-3). These findings hold great promise for advancing technological progress and innovation in the field of aerospace thermal protection materials.