Phase Evolution upon Aging of Air Plasma Sprayed t'-Zirconia Coatings: II-Microstructure Evolution Academic Article uri icon

abstract

  • The correlation between microstructural and phase evolution in aged, yttriapartiallystabilized zirconia, air plasmasprayed coatings is discussed. Freestanding coatings with the dense, vertically cracked structure were isothermally aged at 1482C (2700F) in air. Characterization of the resulting microstructures was conducted using transmission electron microscopy, then compared with a parallel analysis of the phase evolution via synchrotron Xray diffraction (XRD) described in Part I. Additional context was provided by related studies on vapordeposited coatings. Several salient points can be extracted from these assessments. XRD was further validated as a practical method for studying phase stability after clarification of how the possible phases are defined, including the following: (i) the nature of the t phase observed in XRD after phase decomposition has begun and (ii) the relationship between the Yrich tetragonal (t) and Yrich cubic (c) phases reported to coexist via XRD. A strong relationship between the initial microstructure and the subsequent phase destabilization is also reported. As a result, phase evolution is proposed to proceed via two competing routes. The interplay between these mechanisms dictates the incubation time for monoclinic formation within a given coating.

published proceedings

  • JOURNAL OF THE AMERICAN CERAMIC SOCIETY

author list (cited authors)

  • Krogstad, J. A., Leckie, R. M., Kraemer, S., Cairney, J. M., Lipkin, D. M., Johnson, C. A., & Levi, C. G.

citation count

  • 65

complete list of authors

  • Krogstad, Jessica A||Leckie, Rafael M||Kraemer, Stephan||Cairney, Julie M||Lipkin, Don M||Johnson, Curtis A||Levi, Carlos G

editor list (cited editors)

  • Troczynski, T.

publication date

  • January 2013

publisher