Role of Al2O3 in Sintering of Submicron Yttria-Stabilized ZrO2 Powders.

摘要

The use of A12O3 (up to approximately 3.5 wt%) as a sintering aid to promote rapid densification of precipitated yttria (8.0 wt. %) stabilized Zirconia (YSZ) powders in the range 1100 - 1350 C, was investigated. The A12O3 was added as hydrated A1(OH) and dispersed by milling in a 60 : 40 alcohol : water solution, followed by pressing at 205 MPa. Significantly increased densification was obtained with A12O3, even below 1200 C, and optimum densification (>99.0% Th.D.) occured at 1350 C/1 hr. with 0.325 wt% A12O3. These samples exhibited enhanced electrical conductivity and larger grain size (0.3 - 0.5 micrometer). TEM microstructural observations and densification kinetic data indicated a liquid phase assisted sintering mechanism. Solid state doping of the ZrO2 by A1 was inferred from the electrical conductivity data.