Fundamental Physical Properties Of Ta2o5 And Yb2o3 Codoped Strontium Zirconate For Thermal Barrier Coating Applications

An advanced ceramic material with perovskite structure, Ta2O5 (5 mol.-%) and Yb2O3 (5 mol.-%) codoped SrZrO3 [Sr(Zr0.9Ta0.05Yb0.05)O-3, SZTY], was investigated as a material for thermal barrier coating applications. Sr(Zr0.9Ta0.05Yb0.05)O-3 was synthesised using ball milling before solid state sintering, and had a minor second phase of Yb2O3. The material showed good phase stability not only from 200 to 1400 degrees C, but also at a high temperature of 1450 degrees C for a long period, analysed by differential scanning calorimetry and X-ray diffraction respectively. The thermal expansion coefficients of the sintered bulk SZTY were recorded by a high temperature dilatometer and revealed a positive influence on phase transitions of SrZrO3 by codoping Ta2O5 and Yb2O3. The thermal conductivities of SZTY were decreased at least similar to 23% in contrast to that of SrZrO3 and 8YSZ in the testing temperature range. The chemical compatibility of SZTY with 8YSZ or Al2O3 was also evaluated in this study.