CONSTRAINED DENSIFICATION IN BOEHMITE ALUMINA MIXTURES FOR THE FABRICATION OF POROUS ALUMINA CERAMICS

It is demonstrated that inherent constrained densification characteris tics of the bimodal size distributed powders can be utilized to fabric ate porous alpha alumina. Seeded boehmite was mixed with coarse alpha alumina particles to produce various compositions of bimodal mixtures. The densification behaviour of the mixtures was correlated with shrin kage and microstructural evolution. The mixtures sintered at 1200 degr ees C contained more than 30% porosity and the mechanical strength of the mixtures was increased by 2-4 fold relative to the coarse particle s alone with similar porosity (<5 MPa). (C) 1998 Chapman & Hall.