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 degrees 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. (C) 2014 Elsevier Ltd. All rights reserved.