Foam forming of highly porous alumina ceramic paper and its enhancement of mechanical and thermal insulation properties in aerogel composites

Abstract

The strength and toughness of aerogel composites can be enhanced by incorporating alumina ceramic paper as a reinforcing material. However, the production processes often suffer from issues related to poor evenness and low porosity. Herein, alumina ceramic paper with high evenness and porosity was prepared using foam forming technology and utilized as a reinforcing material for alumina-SiO2 aerogel composites. Initially, the hydroxyl groups (Al-OH) of the alumina ceramic fibers were adsorbed onto the hydrophilic moieties of bubbles via hydrogen bonding during the foam forming, which hindered the migration of the fibers and facilitated their dispersion. Subsequently, the alumina ceramic paper was fabricated through the optimization of the squeezing dehydration and defoaming processes. Finally, the alumina-SiO2 aerogel composites were formed via the sol-gel method. The alumina ceramic paper exhibited excellent multifunctional properties, including high porosity and evenness, which significantly enhanced the mechanical and thermal insulation properties of the alumina-SiO2 aerogel composites. In conclusion, highly porous alumina ceramic paper presents significant potential for application in various fields, including automotive, construction, and aerospace.