Thermal barrier coating bonded by (Al2O3–Y2O3)/(Y2O3-stabilized ZrO2) laminated composite coating prepared by two-step cyclic spray pyrolysis

•(Al2O3–Y2O3)/YSZ laminated coatings were fabricated as the bond coat of TBC.•The top coat and substrate were bonded together effectively by such bond coat.•This TBC exhibits very good resistance to oxidation, cracking and spallation.•Such bond coat can suppress oxygen inward diffusion stepwise to avoid oxidation.•Such bond coat exhibits good stress tolerance by its toughening effects.

Thermal barrier coating bonded by (Al2O3–Y2O3)/(Y2O3-stabilized ZrO2) (YSZ) laminated coating has been developed on Ni-based superalloy by two-step cyclic pyrolysis. It is demonstrated, from cyclic oxidation tests at 1100 °C, that YSZ top coat and alloy substrate can be bonded together effectively by the (Al2O3–Y2O3)/YSZ laminated coating, showing good resistance to oxidation, cracking, spallation and buckling. These beneficial effects can be attributed to the sealing effect of the designed multi-sealed compact bond coat with α-Al2O3 layers, the decrease of thermal stresses, the increase of fracture toughness in such bond coat and no interdiffusion between the substrate and bond coat.