# Effect of High-Temperature Aging on the Thermal Conductivity of Nanocrystalline Tetragonal Yttria-stabilized Zirconia

 Title: Effect of High-Temperature Aging on the Thermal Conductivity of Nanocrystalline Tetragonal Yttria-stabilized Zirconia Author: Clarke, David R.; Limarga, Andi M.; Shian, Samuel; Baram, Mor Note: Order does not necessarily reflect citation order of authors. Citation: Limarga, Andi M., Samuel Shian, Mor Baram, and David R. Clarke. 2011. Effect of high-temperature aging on the thermal conductivity of nanocrystalline tetragonal yttria-stabilized zirconia. Acta Materialia 60(15): 5417–5424. Full Text & Related Files: Limarga_Effect.pdf (945.2Kb; PDF) Abstract: The thermal conductivity of yttria-stabilized zirconia (YSZ) thermal barrier coatings increases with high-temperature aging. This common observation has been attributed to the densification of the coatings as porosity sinters out and pores and cracks spheroidize to minimize their surface energy. We show that the thermalconductivity of fully-dense 3 mol. % Y$$_{2}$$O$$_{3}$$ stabilized zirconia (3YSZ) also increases with high-temperature aging, indicating that densification and pore shape changes alone are not responsible for all the observed increase in thermalconductivity of coatings. Instead, there are also increases due to a combination of phase separation and grain growth. The increase in thermal conductivity can be described by a Larson–Miller parameter. It is also found that the increase in thermal conductivity with aging is greatest when measured at room temperature and decreases with increasing measurement temperature. Measured at 1000 °C, the thermal conductivity of zirconia is almost temperature independent and the changes in thermal conductivity with aging are less than 15%, even after aging for 50 h at 1400 °C. Published Version: doi:10.1016/j.actamat.2012.06.054 Terms of Use: This article is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#OAP Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:9887628 Downloads of this work: