Effect of Bondcoat Thickness on High Temperature Hot Corrosion of ZrO₂-8Y₂O₃ Thermal Barrier Coating

Thermal barrier coatings (TBCs) are widely used for industrial and aero turbines. The use of residual fuel oil is well known due to economic reasons, which causes hot corrosion. Hot corrosion over extended exposures reduces durability. Therefore, there is a requirement to develop new design approaches for TBCs in order to operate under hot corrosion environment. In this paper, the effect of bond coat thickness on the hot corrosion resistance was studied. Hot corrosion test were carried out in 50 wt.% Na₂So₄+50 wt.% V₂O₅ molten salt at 950°C for 50 hours. The characterizations of the coatings included X-ray diffraction analysis, scanning electron microscopy and optical microscope. Results indicated that TBCs with thick bond coat exhibited superior hot corrosion resistance to the TBCs with conventional bond coat.