Weakly-agglomerated nanocrystalline (ZrO_2)_(0.9)(Yb_2O_3)_(0.1) powders hydrothermally synthesized at low temperature

摘要

Nanocrystalline ytterbia (10 mol percent)-doped cubic zirconia powders were synthesized by hydrothermal treatment of either an amorphous co-precipitate of hydrated ytterbia-zirconia or of zirconia xerogel in mixture with crystalline Yb_2O_3. The treatments were performed at 110 deg C in the presence of diluted (0.2 M) or concentrated (2.0 M) solution of (K_2CO_3 + KOH) mineralizer and for different reaction times. The reaction times for the full crystallization of cubic-YbSZ-based products were determined for both the employed precursors and for each mineralizer solution. The various fully crystallized products were characterized in their degree of agglomeration and sintered at 1500 deg C for 2 h. The best performance on sintering was achieved with the less agglomerated powder synthesized from the mechanical mixture and in the presence of the diluted solution of the mineralizer. The resulting density was the highest achieved with materials having the same composition.