Phase Stability of t;#8242;-Zirconia-Based Thermal Barrier Coatings: Mechanistic Insights

Journal Article · Mon Nov 07 00:00:00 EST 2011 · J. Am. Ceram. Soc.

DOI:https://doi.org/10.1111/j.1551-2916.2011.04531.x· OSTI ID:1026533

Krogstad, Jessica A; Krämer, Stephan; Lipkin, Don M; Johnson, Curtis A; Mitchell, David R.G.; Cairney, Julie M; Levi, Carlos G ^[1]

---

1. UCSB

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

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: National Science Foundation (NSF)
• OSTI ID: 1026533
• Journal Information: J. Am. Ceram. Soc., Vol. 94, Issue (s1) ; 06, 2011; ISSN 0002-7820
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
COATINGS
KINETICS
MICROSTRUCTURE
PHASE STABILITY
THERMAL BARRIERS
TRANSFORMATIONS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION