Abstract

With increase in operating temperature of gas turbine for higher efficiency, it is necessary to find new materials of TBC for replacement of YSZ. Among candidate materials for future TBCs, zirconate-based oxides with pyrochlore and fluorite are prevailing ones. In this study, phase structure and thermal conductivities of (La_1-xGd_x)_2Zr_2O_7 oxide system are investigated. (La_1-xGd_x)_2Zr_2O_7 system are comprised by selecting La3+/Gd3+ as A-site ions and Zr4+ as B-site ion in A_2B_2O_7 pyrochlore structures. With powder mixture from each oxide, (La_1-xGd_x)_2Zr_2O_7 oxides are fabricated via solid-state reaction at 1600°C. Either pyrochlore or fluorite or mixture of both appears after heat treatment. For the developed phases along (La_1-xGd_x)_2Zr_2O_7 compositions, thermal conductivities are examined, with which the potential of (La_1-xGd_x)_2Zr_2O_7 compositions for TBC application is also discussed.

• Keywords: Thermal barrier coatings;Rare-earth oxides;Pyrochlore-fluorite;Thermal conductivities;