 Recent advancements in finding an alternative for YSZ ceramic topcoat identified many novel ceramics (rare earth zirconates) having superior performance at temperatures above 1200 °C, however with inferior fracture toughness compared to that of YSZ.In addition, such zirconates may have a high concentration of oxygen ion vacancies, which may facilitate oxygen transport and exacerbate the formation of the TGO.With a large enough TGO, spalling of the coating may occur, which is a catastrophic mode of failure for TBCs.