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Effect of Gd content on mechanical properties and erosion durability of sub-stoichiometric Gd2Zr2O7

Authors :
Jamesa L. Stokes
Michael P. Schmitt
Amarendra K. Rai
Douglas E. Wolfe
Brenna L. Gorin
Timothy J. Eden
Dongming Zhu
Source :
Surface and Coatings Technology. 313:177-183
Publication Year :
2017
Publisher :
Elsevier BV, 2017.

Abstract

Advanced thermal barrier coating materials are necessary to improve the efficiency of next-generation gas turbine engines. As such, different TBC chemistries must be developed with enhanced temperature stability above that of 7YSZ (~ 1200 °C) while maintaining thermal and mechanical reliability. The present study investigates the effect of rare earth content on the mechanical properties of ZrO2 TBCs. Various cubic compositions in the ZrO2-GdO1.5 system were investigated in the form of monolithic pellets and coatings with stoichiometric GZO serving as reference. The fracture toughness and erosion durability were evaluated, and it was found that fracture toughness decreased with increasing rare-earth content, 15.66 mol% GdO1.5 yielding 1.25 MPa m1/2, compared to 1.04 MPa m1/2 for GZO (50 mol% GdO1.5). It was observed that the erosion performance of the coatings was much more sensitive to the changes in mechanical properties than the bulk specimens and showed a 125% increase through the fluorite region to GZO whereas the dense pellets only exhibited a 33% increase in erosion behavior. These results indicate that cubic ZrO2 phase with reduced rare-earth content show promise as TBC materials with improved durability over GZO as well as temperature stability in this region of the phase diagram.

Details

ISSN :
02578972
Volume :
313
Database :
OpenAIRE
Journal :
Surface and Coatings Technology
Accession number :
edsair.doi...........21b102ed9a239f7e98acb0c14fd4857d
Full Text :
https://doi.org/10.1016/j.surfcoat.2016.12.045