Ceramics-Silikáty 56 (1) 20-24 (2012)

Fabrication of porous Al₂O₃-based ceramics using combustion synthesized powders

J. Bai, Q. Du, G. Li, C. Li, Y. Zhao, J. Liu

Porous Al₂O₃-based ceramics were fabricated from powders synthesized via a solution combustion process using starch and urea as fuels. Effects of the relative fuel-to-oxidant ratio (φ_e = 1.4, 1.6, 1.8 and 2.0, respectively) on open porosity, pore size distribution and flexural strength of the as-prepared porous Al₂O₃-based ceramics were investigated. Experimental results revealed that the densification ability of the as-synthesized powders increased significantly as φ_e increased, and open porosity, pore size distribution and flexural strength of the porous ceramics exhibited remarkable dependence on the densification ability of the powders instead of the weight fraction of the charred organic residuals in the powders. SEM micrographs disclosed that the porous ceramics from the precursors with φ_e = 1.8 or 2.0 exhibited significantly homogenous microstructures including pore size and pore distribution.

Keywords: Combustion synthesis, Porous ceramics, Al₂O₃