Comparison of Single-Phase and Two-Phase Composite Thermal Barrier Coatings with Equal Total Rare-Earth Content

Amarendra K. Rai, Michael P. Schmitt, Mitchell R. Dorfman, Dongming Zhu, Douglas Edward Wolfe

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Rare-earth zirconates have been the focus of advanced thermal barrier coating research for nearly two decades; however, their lack of toughness prevents a wide-scale adoption due to lack of erosion and thermal cyclic durability. There are generally two methods of improving toughness: intrinsic modification of the coating chemistry and extrinsic modification of the coating structure. This study compares the efficacy of these two methods for a similar overall rare-earth content via the air plasma spray process. The extrinsically toughened coatings were comprised of a two-phase composite containing 30 wt.% Gd2Zr2O7 (GZO) combined with 70 wt.% of a tougher t′ low-k material (ZrO2-2Y2O3-1Gd2O3-1Yb2O3; mol.%), while a single-phase fluorite with the overall rare-earth content equivalent to the two-phase composite (13 mol.% rare-earth) was utilized to explore intrinsically toughened concept. The coatings were then characterized via x-ray diffraction, energy-dispersive spectroscopy, and scanning electron microscopy, and their performance was evaluated via erosion, thermal conductivity, thermal annealing (500 h), and thermal cycling. It was shown that the extrinsic method provided an improved erosion and thermal conductivity response over the single phase, but at the expense of high-temperature stability and cyclic life.

Original languageEnglish (US)
Pages (from-to)556-565
Number of pages10
JournalJournal of Thermal Spray Technology
Volume27
Issue number4
DOIs
StatePublished - Apr 1 2018

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Thermal barrier coatings
Composite coatings
Rare earths
rare earth elements
coatings
Erosion
Coatings
composite materials
erosion
Toughness
Thermal conductivity
toughness
zirconates
thermal conductivity
Fluorspar
Composite materials
Thermal cycling
fluorite
Energy dispersive spectroscopy
Durability

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Rai, Amarendra K. ; Schmitt, Michael P. ; Dorfman, Mitchell R. ; Zhu, Dongming ; Wolfe, Douglas Edward. / Comparison of Single-Phase and Two-Phase Composite Thermal Barrier Coatings with Equal Total Rare-Earth Content. In: Journal of Thermal Spray Technology. 2018 ; Vol. 27, No. 4. pp. 556-565.
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Comparison of Single-Phase and Two-Phase Composite Thermal Barrier Coatings with Equal Total Rare-Earth Content. / Rai, Amarendra K.; Schmitt, Michael P.; Dorfman, Mitchell R.; Zhu, Dongming; Wolfe, Douglas Edward.

In: Journal of Thermal Spray Technology, Vol. 27, No. 4, 01.04.2018, p. 556-565.

Research output: Contribution to journalArticle

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