Elements Diffusion and Phase Transitions in Yb/Y Co-doped Zirconia Ceramic under Molten-salt Corrosive Environment

Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《材料研究学报》

徐俊 陈宏飞 杨光 罗宏杰 高彦峰

Abstract： Ingeneral,high- temperature salt- corrosion may usually induce mechanical stresses and phase transformation within ZrO2，as the main componentof thermal barrier coatings (TBCs), therewith further cause the failure of TBCsfor hot section components of gas turbine. Yb/Y co-doped zirconia (YbYSZ) powder was synthesized by a coprecipitation- calcination method, thenYbYSZ ceramic pallets were obtained by cold pressing and subsequent sintering at high temperature. The corrosion behavior of thepallets coated with a film of powder mixture CaO-MgO-Al2O3-SiO2 (CMAS) was examined in air at 1250℃ for different time intervals. The elemental diffusion and phase transformationwith YbYSZ after high-temperature corrosion wereinvestigated by XRD, SEM and EDS. The results showed that among othersthe elementYbin YbYSZ reacted preferenyially with CMAS and dissolved into the molten saltCMAS. The loss of Yb could suppressed the segragation of Y from the rest YbYSZ.Consequently, it stabilized the metastable tetragonal phase (t'-zirconia). The optimal dose of Yb is 5 mass% for the minimal yield of monoclinic ZrO2 in the YbYSZ after corrosion test.

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