Effect of TiAl3 Content on Thermal Shock Resistance of Bionic Self-healing Thermal Barrier Coatings

Inspired by the self-healing function of biological organisms, Bionic Laser Alloying (BLA) process was adopted to fabricate the bionic self-healing Thermal Barrier Coatings (TBCs). The BLA with different fractions of TiAl3 self-healing agent and Ceria and Yttria-Stabilized Zirconia (CYSZ) on the plasma-sprayed 7YSZ TBCs was carried out by a pulsed Nd: YAG laser. The effect of TiAl3 content on the microstructure, phase composition, and thermal shock behaviors of the bionic self-healing TBCs were investigated. Results indicated that the bionic self-healing TBCs had better thermal shock resistance than that of the as-sprayed TBCs. The thermal shock resistance increased first and then decreased with increasing TiAl3 fraction. The thermal shock resistance of the bionic self-healing TBCs with 15% TiAl3 is triple that of the as-sprayed TBCs. On one hand, the columnar crystals and vertical cracks could improve strain compatibility of TBCs during the thermal shock process; on the other hand, the TiAl3 as a self-healing agent reacted with oxygen in air at high temperature to seal the microcracks, thereby delaying the crack connection.