Research on Damage Repair and Thermal Shock Performance of YSZ Thermal Barrier Coatings Prepared by Slurry Method

To achieve the rapid repair of damaged thermal barrier coatings (TBCs), YSZ coatings were fabricated by the slurry method, and thermally shocked coatings were repaired via secondary slurry deposition. The microstructure, thermal shock behavior, and re-failure mechanism of the repaired coatings were systematically investigated. The results indicate that the as-prepared YSZ coatings mainly consisted of a stable t’-ZrO₂ phase, exhibiting a homogeneous microstructure and structural integrity. The thickness of the original coating is about 100 μm, and the average thermal shock life is about 37 times. After being repaired by secondary slurry deposition, the coating thickness is restored to about 100 μm, the average thermal shock life reaches 22 times retention, and rate the thermal of the shock life is about 60%. The re-failure of the repaired coatings was primarily attributed to the structural mismatch between the repaired layer and the original coating, as well as residual pores and microcracks generated during the secondary sintering process, which induced interfacial stress concentration. Under cyclic thermal stresses, cracks preferentially propagated along the interface, ultimately leading to localized spallation failure. Overall, the slurry method can effectively restore the structural integrity and partially recover the thermal shock resistance of YSZ thermal barrier coatings, demonstrating considerable potential for rapid repair and remanufacturing applications of thermal barrier coatings.