Agglomerate and Particle Size Effects on Sintering Yttria-Stabilized Zirconia

The initial‐, intermediate‐, and final‐stage sintering of fine crystallite yttria‐stabilized zirconia was studied. Experiments were conducted on powder lots of differing agglomerate size and one specially prepared agglomerate‐free powder. Initial‐stage sintering kinetics were compared with a sintering study on larger crystallite size calcia‐stabilized zirconia to access the Herring scaling law. It was found that agglomerates limit attainable green density, interfere with the development of microstructure, impede initial‐stage sintering kinetics, and limit the potential benefit of fine crystallites on final‐stage sintering. An gglomerate free powder centrifuge‐cast to 74% green density was sintered to 99.5% of theoretical density in a 1 h 1100°C cycle, which is ∼300°C lower than necessary for an agglomerated but equal crystallite size powder.