SINTERING KINETICS AND MICROSTRUCTURE DEVELOPMENT OF NANOSCALE Y-TZP CERAMICS

Zirconia samples doped with 3 mol% yttria were prepared by gel precipi tation from a metal chloride solution and their sintering behaviour. c ompared with that of a commercial powder. Dense (relative density 97%) nanoscale ceramics with a mean grain size of 60 nm are obtained after sintering at 1050-degrees-C for 7 h. Important densification mechanis ms in the initial sintering stage are grain boundary sliding and grain boundary diffusion. Grain growth in the final sintering stage seems t o be impurity drag controlled. Extremely low activation energies are o btained for both densification and grain growth in the initial sinteri ng stages. Special attention has been paid to the effect of aggregate size of the precursor powder on the final grain size.