Comparison of hot corrosion behaviors of plasma-sprayed nanostructured and conventional YSZ thermal barrier coatings exposure to molten vanadium pentoxide and sodium sulfate

Abstract

Abstract The purpose of the current study was evaluation and comparison of hot corrosion behaviors of plasma-sprayed conventional and nanostructured yttria stabilized zirconia (YSZ) thermal barrier coatings (TBCs). Hot corrosion studies were performed on the surface of coatings in the presence of a molten mixture of V 2 O 5 +Na 2 SO 4 at 1000 °C for 30 h. Results indicated that the hot corrosion mechanisms of conventional and nanostructured YSZ coatings were similar. The reaction between corrosive salt and Y 2 O 3 produced YVO 4 , leaching Y 2 O 3 from YSZ and causing the detrimental phase transformation of zirconia from tetragonal to monoclinic. The nanostructured coating, as compared to its conventional counterpart, in spite of a further reaction with the corrosive salt, showed a higher degradation resistance during the hot corrosion test due to increased compliance capabilities resulting from the presence of an extra source of porosity associated with the nano-zones.