Hot-Corrosion Behavior of Modified YSZ Thermal Barrier Coating

A modified YSZ thermal barrier coating (TBC) was prepared by simultaneously depositing two components, NiCrAlY and YSZ, on nicked-based superalloy DZ125 via atmospheric plasma spraying. In this study, the sodium salt was deposited on substrate surface at the deposition rate of 3 mg/cm-2. After being heated at 950 °C for 50min, the specimens were cooled to ambient temperature within 10 min. The specimens were recoated after each 10 cycles. Subsequently, the corrosion products were analyzed via X-Ray diffraction and SEM. The results indicated that deterioration of traditional YSZ coating mainly resulted from the fluxing of thermal grown oxides (TGO). Conversely, abnormal growth of TGO and enrichment of molten salt around segmentation crack were not observed in the modified YSZ thermal barrier coating. Moreover, the modified YSZ-TBC exhibited higher thermal resistance than traditional YSZ-TBC in the thermal cycling testing.