Design, fabrication, microstructure, and properties of highly porous alumina whisker foam ceramic

• DOI: 10.1016/j.ceramint.2021.10.065
• Publication Date: 2021-10-13T07:14:55Z
• Authors: Juntao Wu; Hongyu Chen; Xi Luo; Baotong Hu; Shuai Fu; Detian Wan; Yiwang Bao; Qingguo Feng; Salvatore Grasso; Chunfeng Hu
• Keywords: Thermal properties; Porous ceramic; Compressive strength; 02 engineering and technology; alpha-Al2O3 whisker; 0210 nano-technology; Porosity

Abstract In this study, a new type of highly porous ceramic was successfully fabricated from α-Al2O3 whiskers and nano-sized Al2O3 particle slurry by vacuum infiltration with the subsequent annealing in air. It was found that with an increase in the alumina slurry amount or sintering temperature, the porosity of the foam ceramic decreased while its compressive strength increased. The optimal alumina slurry content and sintering temperature were equal to 4 g, and 1350 °C, respectively. The as-synthesised porous foam ceramic exhibited a low density of 0.65 g/cm3, high porosity of 83.51%, high compressive strength of 3.84 MPa, and low thermal conductivity of 1.37 W/m⋅K at room temperature, suggesting its potential applications in high-temperature gas filtration and thermal insulation materials.