Thermal Shock Resistance of 8YSZ Thermal Barrier Coatings by Laser Surface Alloying With Ti ₃ SiC ₂ Self‐Healing Agent

ABSTRACT The 8YSZ thermal barrier coatings (TBCs) was sprayed and then alloyed containing various contents of Ti 3 SiC 2 self‐healing agent and Ceria–Yttria‐Stabilized Zirconia (CYSZ) by fiber laser. The effects of Ti 3 SiC 2 content on the microstructure, phase composition, and thermal shock resistance of the laser‐alloyed coatings were systematically investigated. Results indicated that the laser‐alloyed coating exhibited enhanced resistance to thermal shock. With increasing Ti 3 SiC 2 self‐healing agent content, the lifetime of the laser‐alloyed coating initially increased and subsequently decreased. The laser‐alloyed coating containing 15% Ti 3 SiC 2 exhibited 2.7 times the thermal shock lifetime of the as‐sprayed coating. The enhanced thermal shock resistance originated from two factors: the vertical cracks and columnar crystals that improved strain accommodation during thermal cycling, and the Ti 3 SiC 2 phase that oxidized at high temperatures to fill microcracks and retard crack propagation.