Ultra-fine stabilized zirconia powders, which only contain extremely small aggregates were prepared. The control of agglomerates and aggregates in these powders is of utmost importance in order to obtain highly sinter-reactive ceramics. The very small aggregates appear to be the smallest microstructural units which determine the ultimate packing situation after compaction. Resulting green microstructures and sintering behaviour were studied extensively. The sintering process is seen to proceed via several stages of micro-structural development. During the most important stage, where the ceramic material approaches full density, the observed occurrence of abnormal grain growth strongly influences the ultimate grain size. The extent of abnormal growth is highly dependent on aggregate sizes present in the starting powder.
- Grain size