Effect of Ultrafine Powders Obtained by Mechanical Grinding on the Density of Ceramic Material Made of Aluminum and Zirconium Oxides

The results of grinding powdered and solid zirconium and aluminum oxides in various grinding units, i.e., ball, planetary, and bead mills, are presented. The grinding materials were PSZ-5.5Y brand partially yttrium-stabilized zirconium dioxide (USA) and Almatis CT 3000 GS brand alumina with an α-phase content of >99.0 wt.% (Germany). The use of bead mills with ZrO₂ grinding balls of dimensions 0.6 – 0.8 mm with an M:W ratio of 1:4 and a specific grinding energy of 0.6 – 0.8 kW was advisable to obtain high-purity and ultrafine oxide powders. Solid-phase sintering of the oxide powders was activated and the densities of the ceramic materials increased for aluminum oxide from 3.50 – 3.78 g/cm³ and for zirconium oxide from 5.40 – 5.89 g/cm³ if the ultrafine state of the initial oxide powders was achieved.