Effect of organic additions on the phase composition and crystal growth behavior of 8 wt% yttria-stabilized zirconia nanocrystals prepared via sol–gel process

Abstract

The ZrO2–8 wt% Y2O3 (8YSZ) nanopowders were prepared by sol–gel process using acetic acid (AcOH) as hydrolyst and chelating agent in the water–ethanol solution. The effects of AcOH and ethanol on the phase structure and morphological characteristic of 8YSZ nanopowders were investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Based on these results, the crystal growth behavior of 8YSZ nanopowders was discussed. The results indicate that the addition of ethanol in solvent is not beneficial for the stability of tetragonal phase. However, the stable tetragonal phase in 8YSZ powders can be obtained with water as solvent and the molar ratio AcOH/Zr equal to 1:1. The crystallite size increases with the heat-treatment temperature increasing. In addition, the activation energy for crystal growth in low heat-treatment temperatures is much lower than that in higher heat-treatment temperatures due to the different growth mechanisms.