Effect of thermal treatment at high temperature on phase stability and transformation of YbO and YO co-doped ZrO ceramics.

YO doped ZrO (YSZ) ceramic material is used to protect alloy components worked in high-temperature. But its phase transformation between tetragonal phase and monoclinic phase occurred at 1150 °C leads to YSZ invalid. Therefore, enhancing the phase stability of YSZ is necessary for meeting the demands of the development of thermal barrier coatings (TBC). In this study, X-ray diffraction and Raman spectra were used to explore the phase stability and phase transformation of YbO and YO co-doped ZrO (YbYSZ) ceramics after heat treatment at 1300 °C with different times. The stability of tetragonal phase is improved by tetragonality decreasing with Yb doped. Simultaneously, the incorporation of Yb leads to O-O coupling, which is beneficial for increasing the concentration of oxygen vacancies near the substituted ions, thereby improving the stability of the crystal. The 6.5YbYSZ ceramic has the best stability after heat treatment at 1300 °C for different times.