Unveiling the volcanic ash infiltration resistance of plasma-sprayed next-generation lanthanum cerium tantalum oxide thermal barrier coating at 1250 °C

This study synthesized Ta ₂O ₅-doped La ₂Ce ₂O ₇ powders via solid-state reaction and consolidated them into coatings through plasma spraying. The LCT coating exhibited a thermal conductivity of 0.72–0.93 W/m·K in the temperature range of 30 °C to 800 °C. The deposited coatings were evaluated for their resistance to high-temperature volcanic ash infiltration; during thermochemical interactions at 1250 °C, an apatite-phase silicate-rich interaction layer formed. Such silicate-rich phases are desirable for minimizing volcanic ash infiltration into the porous microstructure. After 24 h, the infiltration depth was approximately 145 µm. A detailed analysis of microstructural characteristics, performance, and degradation mechanisms was discussed.