Ceramics-Silikáty 50 (4) 239-244 (2006)

Alumina ceramics prepared by pressure filtration of alumina powder dispersed in boehmite sol

K. Bodišová, L. Pach, V. Kovár, A. Čerňanský

The alumina ceramics was prepared by pressure filtration of electrostatically stabilized alumina and alumina - boehmite water suspensions and subsequent pressureless sintering of as-prepared compacts. The aggregates formation was avoided by stabilization of initial suspension through the regulation of interparticle forces. Nanoparticle boehmite sol was used as a dispersant for alumina suspension, it acts as a lubricant, and moreover it enhances the handling strength of the green compacts and also its sinterability. The kinetic analysis of sintering confirmed, that the definite boehmite addition (2.7 wt.% in green compact) affects positively the densification. The higher amount of boehmite addition has negative influence; it causes the flocculation of the suspensions and decreases the density of sintered bodies.

Keywords: Alumina ceramics, Submicrometre grain size, Boehmite sol, Dispersant