COMPARATIVE STUDY OF HOT CORROSION BEHAVIOR OF PLASMA SPRAYED YITTRIA AND CERIA STABILIZED ZIRCONIA THERMAL BARRIER COATINGS IN Na2SO4+V2O5 AT 1050 °C

Thermal Barrier Coatings are subjected to spallation and destabilization due to hot corrosion. Ceria Stabilized Zirconia (CSZ)-based TBCs have been intensively investigated for the YSZ replacement because CSZ has a much lower thermal conductivity and a higher expected thermal expansion coefficient than those of YSZ. In this research, Yttria stabilized zirconia (YSZ) and ceria stabilized zirconia (ZrO2 25CeO(2) 2.5Y(2)O(3)) TBCs were fabricated, followed by hot corrosion tests with a Na2SO4+V2O5 salt at 1050 degrees C. The treated samples were characterized using XRD and SEM equipped with EDS. From studies on microscopic failure behavior, the formation of YVO4 crystals and the amount of phase transformations of tetragonal ZrO2 to monoclinic lead to degradation of coatings. Results revealed that CSZ TBCs were better resistant to hot corrosion than YSZ TBCs. The amount of YVO4 crystals and monoclinic ZrO2 in YSZ are much more than CSZ which leads sooner degradation of YSZ than CSZ.