Bonding and Thermal-Mechanical Property of Gradient NiCoCrAlY/YSZ Thermal Barrier Coatings with Millimeter Level Thickness

The thermal insulation properties of barrier coatings (TBCs) can be significantly improved with increasing the coating thickness. However, due to weak bonding high-thickness TBCs, low reliability and short lifetime greatly limits their application under some severe operating conditions. In this study, a novel high-efficiency synchronous dual powder feeding method is used deposit series gradient NiCoCrAlY/YSZ millimeter level tensile strengths residual stress state are evaluated in order explore effect thickness on strength coatings. results suggested that, micro-convex structure at “GC/TC” interface inside “GC” layer, 1000-μm-thickness TBCs 4:6 2:8 hybrid ratios over 44 MPa compared common TBCs. fracture position gradually shifts from NiCoCrAlY bond coat transition zone finally YSZ top owing different concentrations. After cycling tests, exhibits higher life. Some coarse cracks initiate propagate bottom region which mainly expansion mismatch that failure between “BC” layer substrate.