Consolidation of nanoparticle suspensions by centrifugation in non-porous moulds

Alumina and zirconia nanosuspensions with a mean particle size of 100 nm and 15 nm, respectively, were consolidated by centrifugal compaction in non-porous moulds. The nanosuspensions consolidated by high-speed centrifugation were deposited irregularly, resulting in a powder deposit with density profile. The homogeneity of the powder deposits was described and homogeneous and well packed deposit regions were identified. Plate-like bodies were prepared from the homogeneous regions of the deposit. The advantage of regular and dense nanoparticle packing by centrifugal compaction was demonstrated by fabricating transparent alumina and tetragonal zirconia ceramics. The transparent alumina had an in-line transmission of 55% in the visible light at a thickness of 0.8 mm. The transparent tetragonal zirconia reached a dense microstructure with an average grain size of 65 nm and an in-line transmission of 25% at a thickness of 0.5 mm.