Fabrication of porous alumina ceramics from powder mixtures with sol-gel derived nanometer alumina: Effect of mixing method

摘要

This work concerns a systematic study investigating the effect on microstructure, porosity and bending strength of the addition of small amounts of very fine sol-gel derived nanoalumina on a micron-sized alumina powder for the production of highly porous ceramics. Different ways of mixing, with the nanomaterial being either in powder form (gamma-alumina) or in sol state (boehmite sol), were investigated for this purpose. It was observed that when small amounts of nanomaterial (4-6 wt percent) are added both the bending strength and open porosity increase to a level depending significantly on mixing method and level of dispersion of nanoparticles into the coarse matrix. The increase in strength can reach 100 percent in case the nanomaterial is added in powder form and 500 percent in case of mixing in sol state.