Thermophysical Properties of Y₂O₃ and Gd₂O₃ Co-doped SrZrO₃ Thermal Barrier Coating Material

Y2O3 (5mol%) and Gd2O3 (5mol%) co-doped SrZrO3 (Sr(Zr0.9Y0.05Gd0.05)O2.95, SZYG) was synthesized by solid state reaction method. The phase stability of the SZYG powder synthesized at high temperature of 1450℃ for a long period and at temperature range of 200−1400℃ was characterized by XRD and DSC, respectively. The coefficients of thermal expansion (CTEs) of bulk SZYG recorded by a high-temperature dilatometer show that the phase transitions of SrZrO3 is suppressed remarkably by co-doping Y2O3 and Gd2O3. The thermal conductivity of bulk SZYG at 1000℃ is 1.36 W/(m·K), which is 35% lower than that of bulk SrZrO3 and 8YSZ. The good chemi- cal compatibility of SZYG with 8YSZ and Al2O3, is detected after heat-treatment at 1250℃ for 24 h.