New Thermal Barrier Coating System for High Temperature Applications

This paper assesses the thermal shock resistance of ceria (CeO₂) and YPSZ-CeO₂ multilayer coatings produced by plasma and high velocity oxygen flame spraying. The HVOF coatings were denser and had higher oxygen content than the coatings that were plasma sprayed. Optical microscopy revealed that the plasma sprayed coatings had microcracks originating in certain phases, while the HVOF coatings had cracks (perpendicular to the surface) across the entire layer thickness. Based on thermal shock and bond strength testing, multilayer YPSZ-CeO₂ coatings may be of practical value meriting further investigation.