High-temperature cyclic oxidation of micro- and nano-ZrO2–25wt.%CeO2–2.5wt.%Y2O3 thermal barrier coatings at 1300 °C

Abstract

In this study, the high-temperature cyclic oxidation resistance of micro- and nano-ZrO2–25wt.%CeO2–2.5wt.%Y2O3 (CYSZ) thermal barrier coatings (TBCs) was investigated. The TBCs were applied on IN738LC/CoNiCrAlY using the atmospheric plasma spray (APS) technique and subjected to high-temperature cyclic oxidation through 5-h cycles at 1300 °C. Various characterization techniques, including X-ray diffraction (XRD), Raman spectroscopy, nanoindentation, and field-emission scanning electron microscopy (FESEM), were used to assess the TBCs. Results indicated that annealing tetragonal zirconia at 1300 °C can generate antiphase boundary defects. The Young's modulus and hardness of nano- and micro-CYSZ TBCs decrease with the increase of antiphase boundary density. XRD and Raman results, the phase transformation behavior of tetragonal zirconia can be correlated to antiphase boundary density. Furthermore, the study showed that the nano-CSZ TBC has better oxidation resistance than the micro-CYSZ TBC at 1300 °C.