Heat-resistant alumina aerogels serve as prospective thermal insulating materials in the high-temperature fields, whereas the inherent hydrophilicity and thermal coarsening restrict their thermal insulating application. In this study, superhydrophobic, heat-resistant alumina-methylsilsesquioxane hybrid aerogels (AlMSAs) were prepared via in-situ sol-gel method combined with supercritical drying to overcome the aforesaid obstacles. The transformation from hydrophilicity to hydrophobicity is achieved by regulating the molar ratio of methyltriethoxysilane. The aerogel exhibits homogenous superhydrophobicity with contact angle reaching up to 152.6° when the molar ratio of Al to Si is 2 (AlMSA2). AlMSAs show superior heat resistance up to 1300 °C, suffering no α-Al₂O₃ transition and minor grain growth. Quartz fiber reinforced alumina-based aerogel composite (QFAlMSA2) is prepared to study the thermal insulating performance in practical application. The thermal conductivity of QFAlMSA2 reversibly increases by 5.0% subject to 90% relative humidity (36 °C) for one month due to the superhydrophobicity. QFAlMSA2 exhibits a low thermal conductivity of 0.0542 W/(m·K) after being calcined at 1200 °C and a moderate temperature of 113 °C when exposed to a butane flame for 30 min. This study offers meaningful insights into developing alumina-based aerogel materials for high-moisture and high-temperature thermal insulations.

耐热氧化铝气凝胶作为高温领域很有前途的隔热材料，但其固有的亲水性和热粗化性限制了其隔热应用。在这项研究中，通过原位溶胶-凝胶法结合超临界干燥制备了超疏水、耐热的氧化铝-甲基倍半硅氧烷杂化气凝胶 (AlMSAs)，以克服上述障碍。亲水性向疏水性的转变是通过调节甲基三乙氧基硅烷的摩尔比来实现的。当 Al 与 Si 的摩尔比为 2 (AlMSA2) 时，气凝胶表现出均匀的超疏水性，接触角高达 152.6°。AlMSAs 在高达 1300 °C 时表现出优异的耐热性，并且没有 α-Al ₂ O ₃过渡和较小的晶粒生长。制备石英纤维增强氧化铝基气凝胶复合材料（QFAlMSA2），研究实际应用中的隔热性能。由于超疏水性，QFAlMSA2 的热导率在 90% 相对湿度 (36 °C) 下一个月可逆地增加 5.0%。QFAlMSA2 在 1200 °C 下煅烧后表现出 0.0542 W/(m·K) 的低导热率，暴露在丁烷火焰中 30 分钟后表现出 113 °C 的中等温度。这项研究为开发用于高湿和高温隔热的氧化铝基气凝胶材料提供了有意义的见解。