Thermal conductivity of self-assembled nano-structured ZnO bulk ceramics

Yu Zhao; Yongke Yan; Ashok Kumar; Hsin Wang; Wallace D. Porter; Shashank Priya

doi:10.1063/1.4745034

Thermal conductivity of self-assembled nano-structured ZnO bulk ceramics

Yu Zhao, Yongke Yan, Ashok Kumar, Hsin Wang, Wallace D. Porter, Shashank Priya

Research output: Contribution to journal › Article › peer-review

20 Scopus citations

Abstract

In this study, we describe the changes in thermal conductivity behavior of ZnO-Al micro- and nano-two-phase self-assembled composites with varying grain sizes. The reduction in thermal conductivity values of micro-composites was limited to ∼15 for ZnO-4 Al. However, nano-composites exhibited large reduction, by a factor of about three, due to uniform distribution of nano-precipitates (ZnAl ₂O ₄) and large grain boundary area. Interestingly, the micro-composites revealed continuous decrease in thermal conductivity with increase in Al substitution while the nano-composites exhibited the lowest magnitudes for 2 Al concentration. Raman spectra indicated that phonon confinement in ZnO-Al nano-composites causes drastic decrease in the value of thermal conductivity.

Original language	English
Article number	034313
Journal	Journal of Applied Physics
Volume	112
Issue number	3
DOIs	https://doi.org/10.1063/1.4745034
State	Published - Aug 2012

Funding

Authors gratefully acknowledge the financial support provided by NSF/DOE Thermoelectrics Partnership. The work was also supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies as part of the High Temperature Materials Laboratory User Program at Oak Ridge National Laboratory managed by the UT-Battelle LLC, for the Department of Energy under Contract DEAC05000OR22725. One of Authors Yu Zhao would like to thank Charles Farley for his help with Raman spectra measurement.

Funders	Funder number
National Science Foundation	1048708
U.S. Department of Energy	DEAC05000OR22725
Office of Energy Efficiency and Renewable Energy
Oak Ridge National Laboratory
Vehicle Technologies Office
UT-Battelle

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title = "Thermal conductivity of self-assembled nano-structured ZnO bulk ceramics",

abstract = "In this study, we describe the changes in thermal conductivity behavior of ZnO-Al micro- and nano-two-phase self-assembled composites with varying grain sizes. The reduction in thermal conductivity values of micro-composites was limited to ∼15 for ZnO-4 Al. However, nano-composites exhibited large reduction, by a factor of about three, due to uniform distribution of nano-precipitates (ZnAl 2O 4) and large grain boundary area. Interestingly, the micro-composites revealed continuous decrease in thermal conductivity with increase in Al substitution while the nano-composites exhibited the lowest magnitudes for 2 Al concentration. Raman spectra indicated that phonon confinement in ZnO-Al nano-composites causes drastic decrease in the value of thermal conductivity.",

author = "Yu Zhao and Yongke Yan and Ashok Kumar and Hsin Wang and Porter, {Wallace D.} and Shashank Priya",

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AB - In this study, we describe the changes in thermal conductivity behavior of ZnO-Al micro- and nano-two-phase self-assembled composites with varying grain sizes. The reduction in thermal conductivity values of micro-composites was limited to ∼15 for ZnO-4 Al. However, nano-composites exhibited large reduction, by a factor of about three, due to uniform distribution of nano-precipitates (ZnAl 2O 4) and large grain boundary area. Interestingly, the micro-composites revealed continuous decrease in thermal conductivity with increase in Al substitution while the nano-composites exhibited the lowest magnitudes for 2 Al concentration. Raman spectra indicated that phonon confinement in ZnO-Al nano-composites causes drastic decrease in the value of thermal conductivity.

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Thermal conductivity of self-assembled nano-structured ZnO bulk ceramics

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