Abstract
Si3N4 nanocomposites reinforced with 1-, 2-, and 6-vol% single-walled carbon nanotubes (SWNTs) were processed using spark plasma sintering (SPS) in order to control the thermal and electrical properties of the ceramic. Only 2-vol% SWNTs additions were used to decrease the room temperature thermal conductivity by 62% over the monolith and 6-vol% SWNTs was used to transform the insulating ceramic into a metallic electrical conductor (92Sm-1). We found that densification of the nanocomposites was inhibited with increasing SWNT concentration however, the phase transformation from α- to β-Si3N4 was not. After SPS, we found evidence of SWNT survival in addition to sintering induced defects detected by monitoring SWNT peak intensity ratios using Raman spectroscopy. Our results show that SWNTs can be used to effectively increase electrical conductivity and lower thermal conductivity of Si3N4 due to electrical transport enhancement and thermal scattering of phonons by SWNTs using SPS.
Original language | English |
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Pages (from-to) | 391-400 |
Number of pages | 10 |
Journal | Journal of the European Ceramic Society |
Volume | 31 |
Issue number | 3 |
DOIs | |
State | Published - Mar 2011 |
Funding
This work has been financially supported by The Robert Welch Foundation of Texas grant number C1494 , the NSF-AGEP at Rice University grant number HRD-9817555 , Carbon Nanotechnologies Inc., NASA-URETI grant number NC-01-0203 and NASA Ames Research Center grant number NNA04CK63A . Research at The High Temperature Materials Laboratory (HTML) was sponsored by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies, as part of the HTML User Program, Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U. S. Department of Energy under contract number DE-AC05-00OR22725.
Keywords
- Composites
- Electrical properties
- High-temperature materials
- Single-wall carbon nanotubes
- Thermal properties