Sinterability of 8Y-ZrO2 powders hydrothermally synthesized at low temperature

Nanometric yttria (8 mol%)-stabilized zirconia powders were hydrothermally synthesized at 110 jC for 7 days in the presence of dilute (0.20 M) or concentrated (2.0 M) solutions of (KOH +K2CO3) mineralizer. Zirconia xerogel, crystalline Y(OH)3, crystalline Y2O3 and a xerogel of coprecipitated (Y–Zr) hydroxide were used as starting materials. Setting the content of yttria constant and equal to 8 mol%, three types of mixtures were tested. Zirconia xerogel in mixture with crystalline Y2O3, zirconia xerogel in mixture with crystalline Y(OH)3 and, finally, a xerogel of coprecipitated (Y–Zr) hydroxide were hydrothermally treated. The different characteristics of the resulting powders are discussed in terms of both the mineralizer concentration and the type of Y-based precursor used in the hydrothermal treatments, respectively. Weakly agglomerated cubic ZrO2 powders with primary particles bigger in size and without any preliminary treatment show better performances when they are directly sintered at 1500 jC.