Microstructural stability oxidation and hot corrosion resistance of nanostructured Al2O3/YSZ composite compared to conventional YSZ TBC coatings

The spallation of ceramic coating from the bond coat is important problem for TBC systems. And the spallation is caused the oxidation and hot corrosion at the interface of ceramic layer and bond coat. In the present work oxidation and hot corrosion behavior of plasma sprayed nanostructured Al2O3/YSZ composite TBC coatings on Ni-base (IN-738LC) super alloy substrate was studied and compared to conventional YSZ. The coatings have been deposited by plasma spray method. High temperature oxidation test at 1100 °C and hot corrosion test at 1050 °C using Na2SO4 and V2O5 molten salts were performed on the coatings. The experimental results showed nanostructured Al2O3/YSZ composite coating had higher oxidation and hot corrosion resistance than those of the conventional YSZ coating. The microstructural analysis indicated that the growth of TGO was much less for this nanostructured Al2O3/YSZ composite coating while it reduced infiltration of both oxygen and aggressive molten salt.