Growth Of Thermally Grown Oxide On (Ni,Pt)Al Bondcoat During Short Term Oxidation

The growth and microstructure of the thermally grown oxide (TGO) play an important role in the durability and the reliability of the thermal barrier coatings (TBCs). In this study, the growth and the microstructure of the TGO, underneath the electron beam physical vapor deposited (EB-PVD) ZrO 2-8wt.%Y 2O 3 (8YSZ) topcoat were examined as a function of surface treatment of (Ni,Pt)Al bondcoat and short term oxidation by using focused ion beam (FIB) and scanning transmission electron microscopy (STEM). While the TGO developed consisted of a mixed-oxide zone (MOZ) and continuous-columnar oxide zone (COZ) for as-coated (Ni,Pt)Al bondcoat, the TGO consisted only of COZ for grit-blasted (Ni,Pt)Al bondcoat. Numerous voids were observed near the interface between the MOZ and COZ on the as-coated bondcoat TBC