Local residual stress evolution of highly irregular thermally grown oxide layer in thermal barrier coatings

Local residual stress in thermally grown oxide (TGO) layers is the primary cause of failure thermal barrier coating (TBC) systems, especially TBCs prepared by air plasma spray (APS) with a highly irregular TGO. Herein, distribution and evolution TGO layer APS were investigated as function oxidation time. The was measured from cross-sectional micrographs converted to actual inside coatings before sectioning. exhibited significant inhomogeneity at different locations. Stress conversion occurred across thickness; near yttria-stabilised zirconia (YSZ) component compressive stress, whereas that along bond coat under tensile stress. also discussed. These analyses may provide better understanding mechanism TBCs.