Effects of Pre-Oxide Layer Thickness on Thermal Cyclic Behavior of Thermal Barrier Coatings
Conventional two-layered structure thermal barrier coatings (TBCs) with different pre-oxide layer thicknesses were produced by EB-PVD onto Ni-based superalloy. The pre-oxide layer with different thicknesses was formed after vacuum heat treatment for 2 hours and before ceramic deposition by heating the bond coat to 1323K in air for different times. It has been found that with pre-oxide layer thickness increasing from 1μm to 3.1μm, the growth rate of thermally grown oxide (TGO) increased during thermal cycling test and the thermal cyclic lifetime of TBCs decreased from 730hs to 400hs Two failure modes were observed for TBCs with different pre-oxide layer thicknesses and different TGO layer growth rates.
Wei Pan and Jianghong Gong
D. B. Zhang et al., "Effects of Pre-Oxide Layer Thickness on Thermal Cyclic Behavior of Thermal Barrier Coatings", Key Engineering Materials, Vols. 336-338, pp. 1746-1749, 2007