Abstract: Conventional two-layered structure thermal barrier coatings (TBCs) were preparedonto γ'-Ni3Al based alloy IC-6 by electron beam physical vapor deposition (EB-PVD).Isothermal oxidation and thermal cycling tests were carried out to investigate theeffect of Mo content at the interface between bond coat and ceramic top coat causedby diffusion. It has been found that the alloy coated with TBCs presented the lowestoxidation weight gain value for the reason that the ceramic top coat in TBC systemcan effectively stop Mo oxides evaporating. The life time of TBCs has close relationwith Mo content at the interface between the bond coat and top coat. Spallation ofceramic top coat occurred during thermal cyclic testing when Mo atoms accumulatedat the interface up to certain amount to decline the combination between the bond coatand top coat.

Key words: EB-PVD, thermal barrier coatings (TBCs), thermal cyclic, dif-fusion