Zirconia-yttria (8 mol%) powders hydrothermally synthesized from different Y-based precursors

Nanometric powders of yttria (8 mol%) stabilized cubic zirconia were hydrothermally synthesized from amorphous zirconia at 110 °C for 7 days in the presence of (KOH+K2CO3) mineralizer solutions at different concentrations. Different Y-based precursors were employed in mixtures with zirconia xerogel: crystalline Y(OH)3, crystalline Y2O3 and Y(OH)3 xerogel as a Zr–Y coprecipitate. The type of Y-based precursor and the concentration of the mineralizer noticeably affect the characteristics of cubic ZrO2 crystallized as the main phase. The resulting powders differ, in fact, in terms of reactivity, degree of agglomeration, amount of both monoclinic ZrO2 and uncrystallized zirconia. Regarding the sinterability of the various powders, poor defects YSZ-based ceramics were produced from powders characterized by crystallites relatively larger in size. Such characteristics are typical of the powder hydrothermally synthesized from the mechanical mixture of crystalline Y2O3 and zirconia xerogel in the presence of dilute solution of the mineralizer.