Microstructure and sintering kinetics of highly reactive ZrO2-Y2O3 ceramics

Ultra-fine stabilized zirconia powders, which contain extremely small aggregates, were prepared. The control of agglomerates in these powders is of utmost importance in obtaining 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 proceeds via several stages of microstructural 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. 12pp 11fig