Phase Stability of t′-Zirconia-Based Thermal Barrier Coatings: Mechanistic Insights

摘要: The temperature capability of yttria-stabilized zirconia thermal barrier coatings (TBCs) is ultimately tied to the rate evolution “nontransformable” t′ phase into a depleted tetragonal form predisposed monoclinic transformation on cooling. phase, however, has been shown decompose in small fraction time necessary phase. Instead, modulated microstructure consisting coherent array Y-rich and Y-lean lamellar phases develops early process, with mechanistic features suggestive spinodal decomposition. Coarsening this leads loss coherency form, making kinetics not initial decomposition, critical factor determining stability TBCs. Transmission electron microscopy be essential only for characterizing but also proper interpretation X-ray diffraction analysis.