Thermal conductivity and erosion durability of composite two-phase air plasma sprayed thermal barrier coatings

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

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

To enhance efficiency of gas turbines, new thermal barrier coatings (TBCs) must be designed which improve upon the thermal stability limit of 7. wt.% yttria stabilized zirconia (7YSZ), ~. 1200. °C. This tenant has led to the development of new TBC materials and microstructures capable of improved high temperature performance. This study focused on increasing the erosion durability of cubic zirconia based TBCs, traditionally less durable than the metastable t' zirconia based TBCs. Composite TBC microstructures composed of a low thermal conductivity/high temperature stable cubic Low-k matrix phase and a durable t' Low-k secondary phase were deposited via APS. Monolithic coatings composed of cubic Low-k and t' Low-k were also deposited, in addition to a 7YSZ benchmark. The thermal conductivity and erosion durability were then measured and it was found that both of the Low-k materials have significantly reduced thermal conductivities, with monolithic t' Low-k and cubic Low-k improving upon 7YSZ by ~. 13% and ~. 25%, respectively. The 40. wt.% t' Low-k composite (40. wt.% t' Low-k - 60. wt.% cubic Low-k) showed a ~. 22% reduction in thermal conductivity over 7YSZ, indicating even at high levels, the t' Low-k secondary phase had a minimal impact on thermal conductivity in the composite coating. It was observed that a mere 20. wt.% t' Low-k phase addition can reduce the erosion of a cubic Low-k matrix phase composite coating by over 37%. Various mixing rules were then investigated to assess this non-linear composite behavior and suggestions were made to further improve erosion durability.

Original languageEnglish (US)
Pages (from-to)44-52
Number of pages9
JournalSurface and Coatings Technology
Volume279
DOIs
StatePublished - Oct 15 2015

Fingerprint

Thermal barrier coatings
Sprayed coatings
durability
erosion
Erosion
Thermal conductivity
Durability
thermal conductivity
Plasmas
coatings
Turbines
composite materials
air
Composite materials
turbines
Air
Composite coatings
Zirconia
Microstructure
zirconium oxides

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Schmitt, Michael P. ; Rai, Amarendra K. ; Zhu, Dongming ; Dorfman, Mitchell R. ; Wolfe, Douglas Edward. / Thermal conductivity and erosion durability of composite two-phase air plasma sprayed thermal barrier coatings. In: Surface and Coatings Technology. 2015 ; Vol. 279. pp. 44-52.
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abstract = "To enhance efficiency of gas turbines, new thermal barrier coatings (TBCs) must be designed which improve upon the thermal stability limit of 7. wt.{\%} yttria stabilized zirconia (7YSZ), ~. 1200. °C. This tenant has led to the development of new TBC materials and microstructures capable of improved high temperature performance. This study focused on increasing the erosion durability of cubic zirconia based TBCs, traditionally less durable than the metastable t' zirconia based TBCs. Composite TBC microstructures composed of a low thermal conductivity/high temperature stable cubic Low-k matrix phase and a durable t' Low-k secondary phase were deposited via APS. Monolithic coatings composed of cubic Low-k and t' Low-k were also deposited, in addition to a 7YSZ benchmark. The thermal conductivity and erosion durability were then measured and it was found that both of the Low-k materials have significantly reduced thermal conductivities, with monolithic t' Low-k and cubic Low-k improving upon 7YSZ by ~. 13{\%} and ~. 25{\%}, respectively. The 40. wt.{\%} t' Low-k composite (40. wt.{\%} t' Low-k - 60. wt.{\%} cubic Low-k) showed a ~. 22{\%} reduction in thermal conductivity over 7YSZ, indicating even at high levels, the t' Low-k secondary phase had a minimal impact on thermal conductivity in the composite coating. It was observed that a mere 20. wt.{\%} t' Low-k phase addition can reduce the erosion of a cubic Low-k matrix phase composite coating by over 37{\%}. Various mixing rules were then investigated to assess this non-linear composite behavior and suggestions were made to further improve erosion durability.",
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Thermal conductivity and erosion durability of composite two-phase air plasma sprayed thermal barrier coatings. / Schmitt, Michael P.; Rai, Amarendra K.; Zhu, Dongming; Dorfman, Mitchell R.; Wolfe, Douglas Edward.

In: Surface and Coatings Technology, Vol. 279, 15.10.2015, p. 44-52.

Research output: Contribution to journalArticle

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T1 - Thermal conductivity and erosion durability of composite two-phase air plasma sprayed thermal barrier coatings

AU - Schmitt, Michael P.

AU - Rai, Amarendra K.

AU - Zhu, Dongming

AU - Dorfman, Mitchell R.

AU - Wolfe, Douglas Edward

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N2 - To enhance efficiency of gas turbines, new thermal barrier coatings (TBCs) must be designed which improve upon the thermal stability limit of 7. wt.% yttria stabilized zirconia (7YSZ), ~. 1200. °C. This tenant has led to the development of new TBC materials and microstructures capable of improved high temperature performance. This study focused on increasing the erosion durability of cubic zirconia based TBCs, traditionally less durable than the metastable t' zirconia based TBCs. Composite TBC microstructures composed of a low thermal conductivity/high temperature stable cubic Low-k matrix phase and a durable t' Low-k secondary phase were deposited via APS. Monolithic coatings composed of cubic Low-k and t' Low-k were also deposited, in addition to a 7YSZ benchmark. The thermal conductivity and erosion durability were then measured and it was found that both of the Low-k materials have significantly reduced thermal conductivities, with monolithic t' Low-k and cubic Low-k improving upon 7YSZ by ~. 13% and ~. 25%, respectively. The 40. wt.% t' Low-k composite (40. wt.% t' Low-k - 60. wt.% cubic Low-k) showed a ~. 22% reduction in thermal conductivity over 7YSZ, indicating even at high levels, the t' Low-k secondary phase had a minimal impact on thermal conductivity in the composite coating. It was observed that a mere 20. wt.% t' Low-k phase addition can reduce the erosion of a cubic Low-k matrix phase composite coating by over 37%. Various mixing rules were then investigated to assess this non-linear composite behavior and suggestions were made to further improve erosion durability.

AB - To enhance efficiency of gas turbines, new thermal barrier coatings (TBCs) must be designed which improve upon the thermal stability limit of 7. wt.% yttria stabilized zirconia (7YSZ), ~. 1200. °C. This tenant has led to the development of new TBC materials and microstructures capable of improved high temperature performance. This study focused on increasing the erosion durability of cubic zirconia based TBCs, traditionally less durable than the metastable t' zirconia based TBCs. Composite TBC microstructures composed of a low thermal conductivity/high temperature stable cubic Low-k matrix phase and a durable t' Low-k secondary phase were deposited via APS. Monolithic coatings composed of cubic Low-k and t' Low-k were also deposited, in addition to a 7YSZ benchmark. The thermal conductivity and erosion durability were then measured and it was found that both of the Low-k materials have significantly reduced thermal conductivities, with monolithic t' Low-k and cubic Low-k improving upon 7YSZ by ~. 13% and ~. 25%, respectively. The 40. wt.% t' Low-k composite (40. wt.% t' Low-k - 60. wt.% cubic Low-k) showed a ~. 22% reduction in thermal conductivity over 7YSZ, indicating even at high levels, the t' Low-k secondary phase had a minimal impact on thermal conductivity in the composite coating. It was observed that a mere 20. wt.% t' Low-k phase addition can reduce the erosion of a cubic Low-k matrix phase composite coating by over 37%. Various mixing rules were then investigated to assess this non-linear composite behavior and suggestions were made to further improve erosion durability.

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