Effect of pre-oxidation on the failure mechanisms of EB-PVD thermal barrier coatings with (Ni,Pt)Al bond coats

In order to clarify the effect of pre-oxidation for (Ni,Pt)Al bond coat on failure modes of TBCs, cyclic oxidation behavior of thermal barrier coatings system with both pre-oxidized and normal (Ni,Pt)Al bond coats was investigated at 1100 °C. The results indicated that thermal cycling resistance of TBCs was dramatically enhanced by pre-oxidation, where thinner and lower residual stress oxide scale, lighter rumpling of the BC/TGO interface were achieved pre-oxidized. The failure modes of these two TBCs were completely diverse. Besides, the lower oxygen partial pressure effectively enhanced transformation from θ to α-Al2O3 during pre-oxidation.