TY - JOUR
T1 - High temperature, electrically conductive graphite composites for space nuclear power
AU - Lake, M. L.
AU - Woollam, J. A.
AU - Dillon, R. O.
AU - Ahmed, A.
AU - Brito, K. K.
N1 - Funding Information:
The authors wish to acknowledge the experimental contributions of J. Hagerhorst, A. Aplin, and J. Baer. This research is being conducted with the sponsorship of the United States Air Force Wright Aeronautical Laboratories under contract #F33615-87-C-2833, and by Space Power Inc., San Jose, CA.
Publisher Copyright:
© 1988 SPIE. All rights reserved.
PY - 1988/4/6
Y1 - 1988/4/6
N2 - Space nuclear power systems require materials with low density, high thermal conductivity, and high electrical conductivity at elevated temperatures. Vapor grown carbon fiber (VGCF) is a novel material which is a good candidate for these structures. VGCF has been shown to have combined characteristics of thermal conductivity, strength and modulus which exceed values for PAN and pitch -based fibers, and has an electrical conductivity comparable to single crystal graphite. Major thrusts of the current research are to explore growth and processing of vapor grown fibers, and to study the effect of boron doping on the electrical properties of VGCF. Doping of graphite is known to change the distribution of electrons between energy levels in carbon, to enhance graphitization, and to modify the chemical composition of the surface of carbon fibers. Measurements of electrical resistivity as a function of temperature from 4 K to 2700 K have been obtained. The product of resistivity times density of annealed VGCF has been observed to be substantially lower than that of refractory metals at temperatures exceeding 1000 K, suggesting the utility of this unique material as an electrical conductor in space nuclear power thermionic conversion and other high temperature applications.
AB - Space nuclear power systems require materials with low density, high thermal conductivity, and high electrical conductivity at elevated temperatures. Vapor grown carbon fiber (VGCF) is a novel material which is a good candidate for these structures. VGCF has been shown to have combined characteristics of thermal conductivity, strength and modulus which exceed values for PAN and pitch -based fibers, and has an electrical conductivity comparable to single crystal graphite. Major thrusts of the current research are to explore growth and processing of vapor grown fibers, and to study the effect of boron doping on the electrical properties of VGCF. Doping of graphite is known to change the distribution of electrons between energy levels in carbon, to enhance graphitization, and to modify the chemical composition of the surface of carbon fibers. Measurements of electrical resistivity as a function of temperature from 4 K to 2700 K have been obtained. The product of resistivity times density of annealed VGCF has been observed to be substantially lower than that of refractory metals at temperatures exceeding 1000 K, suggesting the utility of this unique material as an electrical conductor in space nuclear power thermionic conversion and other high temperature applications.
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U2 - 10.1117/12.943633
DO - 10.1117/12.943633
M3 - Conference article
AN - SCOPUS:84914754155
SN - 0277-786X
VL - 871
SP - 89
EP - 95
JO - Proceedings of SPIE - The International Society for Optical Engineering
JF - Proceedings of SPIE - The International Society for Optical Engineering
T2 - Space Structures, Power, and Power Conditioning 1988
Y2 - 11 January 1988 through 17 January 1988
ER -