High-temperature thermal properties of yttria fully stabilized zirconia ceramics

In this study, the dependences of yttria content, porosity and grain size on the thermal properties of Y2O3 stabilized ZrO2 (YSZ) ceramics were investigated. YSZ ceramics were synthesized by the solid state reaction method. The phase, microstructure and thermal properties of YSZ ceramics were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and laser-flash apparatus (LFA), respectively. The results indicated that the specific heat capacity of YSZ increased with the increase of temperature and decreased with the increase of yttria content. As the temperature increased, the thermal diffusivity and conductivity of YSZ ceramics were decreased, whereas their variations for 16YSZ, 18YSZ and 20YSZ were much less pronounced than those for 12YSZ and 14YSZ. At a given temperature, the thermal conductivity of YSZ was opposite to yttria content. The thermal conductivity of YSZ ceramics almost linearly decreased with the increase of porosity. In addition, the grain size also had a great influence on the thermal conductivity.