Comparative Study of Plasma Sprayed Yttria and Ceria Stabilized Zirconia Properties

Thermal Barrier Coatings are subjected to spalling and destabilization due to hot corrosion. Recently, Ceria Stabilized Zirconia-based TBCs have been intensively investigated for the Yttria stabilized zirconia replacement because ceria stabilized zirconia has a much lower thermal conductivity and a higher expected thermal expansion coefficient than those of Yttria stabilized zirconia. In this research, Yttria stabilized zirconia and ceria stabilized zirconia (ZrO2 25CeO2 2.5Y2O3) TBCs were fabricated, followed by hot corrosion tests with a Na2SO4+V2O5 salt at 1050°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 ceria Stabilized Zirconia TBCs had better resistant to hot corrosion than Yttria stabilized zirconia TBCs. The amount of YVO4 crystals and monoclinic ZrO2 in Yttria stabilized zirconia are much more than ceria stabilized zirconia which leads to faster degradation of Yttria stabilized zirconia than ceria stabilized zirconia. The strength of the Adhesive coatings of the substrate was also measured in this study.