Investigation of ternary rare earth oxide-doped YSZ and its high temperature stability

Abstract Due to the limited temperature capability of widely used yttria partially stabilized zirconia (YSZ), considerable effort has been directed towards developing promising thermal barrier coating materials for applications above 1200 °C. La2O3-Gd2O3-Yb2O3-Y2O3-doped zirconia (LGYYSZ), as a promising ceramic for advanced thermal barrier coatings, was designed and prepared. The LGYYSZ ceramics consist of tetragonal double-prime phase and cubic phase, and no new phase appears after long-term annealing. The thermal expansion coefficients of LGYYSZ are comparable to the value of YSZ. The values of the thermal conductivities of 0.5LGYYSZ and 1.0LGYYSZ are 1.34 W/(mK) and 1.21 W/(mK) at 1000 °C, respectively, which are approximately 30–40% lower than that of YSZ. Due to the rare earth ions with different radii/masses and the compound effect of multiple point dislocations, a significant improvement of the sintering resistance of LGYYSZ ceramics was observed above 1400 °C with La3+ dopant.