Characterization of YSZ Ceramic Nanopowders Synthesized at Different Temperatures via Polyacrylamide Gel Method

Abstract

Tetragonal zirconia (T-ZrO₂) ceramic nanopowders stabilized with 3 mol% Y₂O₃ were synthesized via polyacrylamide gel method, using ZrOCl₂·8H₂O and Y(NO₃)₃·6H₂O as raw materials. The effect of temperature on phase composition and morphology of YSZ nanopowders and sintering behavior of YSZ ceramics was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Vickers hardness tester. The aging-resistance of YSZ ceramics was measured by means of aging experiments. The results demonstrated that the phase composition of YSZ ceramic nanopowders had no obvious change and it was composed of T-ZrO₂. Particle size of well-dispersed YSZ ceramic nanopowders increased from 17 to 35 nm with increasing calcining temperature from 600 to 800 °C. There was noticeable negative correlation between calcining temperature and the relative density of YSZ ceramic at the same sintering temperature. The aging experiments showed that water vapor facilitated tetragonal to monoclinic phase transformation, and the sample that had smaller grain size exhibited better aging-resistance. It can be concluded that when the calcining temperature is 600 C and sintering temperature is 1 550 C, the relative density and hardness of YSZ ceramic arrive at the peak of 96.64% and 11.135 GPa respectively, and it has less microcracks and excellent aging-resistance.

Keywords

YSZ nanopowders / polyacrylamide gel method / sintering behavior / aging-resistance / grain size