Nanocrystalline zirconia based powders synthesized by hydrothermal method

Nanocrystalline powders in the ZrO2-Y2O3-CeO2-CoO-Al2O3 system with 1 and 10 mol% Al2O3 were prepared via hydrothermal treatment in alkaline medium. The characteristics of nanocrystalline powders after heat treatment in the temperature range from 500 to 1200 °C were investigated by XRD phase analysis, scanning electron microscopy, petrography and BET measurements. It was found that hydrothermally treated powders contained metastable low-temperature cubic solid solution based on ZrO2 and addition of Al2O3 increased temperature of phase transformation of the metastable cubic- ZrO2 to tetragonal-ZrO2. It was evidenced that both powders remained nanocrystalline after all processing steps with the average particle sizes from 8 to 20 nm. The addition of 0.3 mol% CoO allows one to obtain composites with good sinterability at 1200 °C.