Processing of zirconia nanoceramics from a coarse powder

作者：Kocjan Andraz^*; Pouchly Vaclav; Shen Zhijian

来源：Journal of the European Ceramic Society, 2015, 35(4): 1285-1295.

DOI：10.1016/j.jeurceramsoc.2014.10.022

• Zirconia
• Nanoceramic
• Porosity
• Sintering
• Microstructure

We have merged the benefits of coarse-grained and nanocrystalline powders by the consolidation and sintering of coarse, yet nanostructured, mesoporous Y-TZP powder. The powder was composed of loosely aggregated, nanoscale crystallites, which can be seen as secondary particles or agglomerates. Their homogeneous, defect-free packing proved to be a viable pathway for the processing of zirconia nanoceramics. The powder consolidation yielded homogeneous green bodies with hierarchical heterogeneities in terms of intra- and inter-particle pore packing. The hierarchical heterogeneities had a pronounced effect on the densification and grain growth. The intra-particle pore coalescence along with a "frozen" interparticle porosity, prolonged the pore-pinning effect, separating the densification and grain-growth mechanisms. Increased heating rates promoted the grain-growth and densification via a competitive mechanism of primary crystallite ordered coalescence, while by applying pressure, the crystallite growth was completely prevented, making such a coarse powder suitable for the fabrication of zirconia nanoceramics.

• 出版日期2015-4