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 (US) |
|---|---|
| Article number | 034313 |
| Journal | Journal of Applied Physics |
| Volume | 112 |
| Issue number | 3 |
| DOIs | |
| State | Published - Aug 2012 |
| Externally published | Yes |
Bibliographical note
Funding Information: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.