Hot Corrosion Behavior of Functional Graded Material Thermal Barrier Coating (RESEARCH NOTE)

In this paper a functional graded material (FGM) thermal barrier coating (TBC) is prepared using Atmospheric Plasma Spraying (APS) method. The FGM layers were deposited by varying the feeding ratio of CYSZ/NiCrAlY and conventional CYSZ on a NiCrALY-coated Inconel 738 substrates. Hot corrosion behavior, bonding strength and the related failure mechanisms of a conventional TBC and a FGM TBC are investigated. Hot corrosion studies were conducted in presence of 45% Na2SO4+ 55% V2O5 molten salt at 1000 oC temperature. The as-sprayed coatings and heat-treated coatings were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Exposing to hot corrosion test, the FGM TBC showed better chemical stability and higher life service in comparison to the conventional TBC. As a result, functional graded material thermal barrier coating exhibited very promising potential as a novel TBC material.