Thermal Conductivity Behavior of Boron Carbides
Knowledge of the thermal conductivity of boron carbide is necessary to evaluate its potential for high temperature thermoelectric energy conversion applications. We have measured the thermal diffusivity of hot-pressed boron carbide B1-xCx samples as a function of composition (0.1 ≤ x ≤ 0.2), temperature (300 K to 1700 K) and temperature cycling. These data in concert with density and specific heat data yield the thermal conductivities of these materials. We discuss these results in terms of a structural model that has been previously advanced by two of us (D.E. and C.W.) to explain the electrical transport data. Some novel mechanisms for thermal conduction are briefly discussed.
KeywordsThermal Conductivity Thermal Diffusivity Boron Carbide Thermal Transport Lattice Thermal Conductivity
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- Emin, D. and Wood, C., “Small-Polaron Electronic Transport in Boron Carbides,” Proceedings of the 18th IECEC, 1, 222–225, Orlando, FL, Aug. 22–26 (1983).Google Scholar
- Deem, H. W. and Lucks, C. F., “Thermal Conductivity of Boron Carbide from 100 C to 800 C,” Battelle Memorial Institute Report No. BMI-731, 1951 (unpublished); Nucl. Sci. Abstr. 6, 915 (1952).Google Scholar
- Hedge, J. C.; Kostenko, C.; and Lang, J. I., Illinois Institute of Technology Research Institute, Technical Documentary Report Nos. ASD-TDR-63-597 and AD-424375, 1963 (unpublished; see Chem. Abstr. 61, 10433d, 1964 ).Google Scholar
- Boiko, N. V. and Shpil’rain, E. E., “Some Questions on the Method of Experimentally Studying the Heat Conductivity of Materials at High Temperatures,” Sov. Phys. High Temp. 2, 493–500 (1964)Google Scholar
- Nuclear Systems Materials Handbook, Vol. 1 Design Data. Part III Group 1 Section 1. p 1.0, 1. 1.Google Scholar
- Gilchrist, K. E. and Preston, S. D., “Thermophysical Property Measurements on Some Neutron Absorbing Materials,” High Temp.-High Pres. 11, 643–651 (1979).Google Scholar
- Taylor, R. E., “Heat-Pulse Thermal Diffusivity Measurements,” High-Temp.-High Press. 11, 43–58 (1979).Google Scholar
- Data supplied by D. Elwell, Stanford University, using a Dupont Differential Scanning Calorimeter.Google Scholar
- From thermal diffusivity data supplied by R. E. Taylor, Purdue University, and confirmed by JPL, using the flash method. An absolute determination of thermal conductivity by G. Slack, G. E. Research, yielded a fairly temperature independent value of -0.068 ± 0.002 W/K-cm for B0.9C0.1 in the vicinity of room temperature in essential agreement with B0.9C0.1 (20–1).Google Scholar