Evaluation of hot corrosion behavior of plasma sprayed scandia and yttria co-stabilized nanostructured thermal barrier coatings in the presence of molten sulfate and vanadate salt

In this study, the substrates of Inconel 738-LC superalloy were first sprayed with an NiCrAlY bondcoat and then with a nanostructured scandia (3.6 mol%) and yttria (0.4 mol%) co-stabilized zirconia (4SYSZ) topcoat by air plasma spraying (APS). Hot corrosion studies of plasma sprayed thermal barrier coatings (TBCs) were conducted in 45 wt% Na2SO4 + 55 wt% V2O5 molten salt at 910 °C for 300 h. The results show that the failure of this TBC occurred in bondcoating layer due to the formation of mixed oxide (NiO, NiAl2O4 and NiCr2O4) in this layer.