Formation of porous Al2O3-SiO2 composite ceramics by electrostatic assembly

Porous ceramics possess many unique properties that are used for multifunctional applications. This study reports on a feasible formation of Al2O3-SiO2 composite ceramics using an electrostatic assembly technique without any use of pore former. Homogeneously SiO2-particles-decorated Al2O3 composites were first obtained using electrostatic assembly. The amount of SiO2 added was varied at 12 and 40 vol.%. The Al2O3-SiO(2 )composite powders were then pressed into green bodies and sintered at different temperatures from 1300 to 1600 degrees C. The morphologies, open porosity and crystallinity as well as the mechanical properties of the Al2O3-SiO(2 )composite ceramics were systematically characterized. The microstructural observation demonstrated that the porosity was altered by changing the amount of SiO2 added as well as sintering temperature. A mullite phase was observed after sintering at 1600 degrees C. The elastic modulus and yield stress were found to correlate with the open porosity of the Al2O3-SiO2 composites. (C) 2020 The Ceramic Society of Japan. All rights reserved.