Synthesis and Characterization of Lanthanum Cerium Oxide Compounds for Thermal Barrier Coating Applications

Lanthanum-cerate (La2Ce2O7) is a potential candidate for thermal barrier coating (TBC) applications due to its long-term phase stability at operating conditions, in contrast to Yttria-stabilized zirconia. In addition, it possesses low thermal conductivity and a large coefficient of thermal expansion (CTE) at high temperatures, and its magnitude is closely similar to CTE of underlying bond-coat, in a TBC system. However, limited literature exists with regards to the large-scale synthesis of lanthanum-cerate using commercially available precursors, which is crucial for its utilisation in next-generation aero-turbines. In this work, mixed oxide of lanthanum and cerium of various compositions and La2Ce2O7 stoichiometric compound were processed using indigenously available precursors, through facile synthesis, in a cost-effective manner. Firstly, the thermal decomposition and phase evolution behavior of as-received lanthanum and cerium precursors were studied using thermo-gravimetric analysis and X-ray diffraction, respectively. Subsequently, lanthanum-cerium mixed oxides were prepared through two processing routes such as (i) evaporation, drying and calcination, (ii) solid-state technique, respectively and the feasibility of large-scale synthesis of single-phase lanthanum-cerate compound is elucidated.