Thermal expansivity and conductivity of pure and silicon-alloyed pyrocarbons

✍ Scribed by R.J. Price; K. Koyama

• Publisher: Elsevier Science
• Year: 1974
• Tongue: English
• Weight: 592 KB
• Volume: 12
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(74)90023-2

✦ Synopsis

Measurements

were made of the thermal expansivitv (22"-1000°C) and the thermal conductivity (22"-800°C) of isotropic pyrocarbons deposited in fluidized beds and containing up to 34 wt% silicon in the form of @-silicon carbide particles. The thermal expansivity of the pure carbons was proportional to their density, while thar of the silicon-alloyed carbons decreased with increasing silicon content, falling from 6.3 x 1O~""C' for material containing 4 wt%, silicon to 4.6 X 1O~""C' for material with 34 wtg silicon. The therma conductivity of both pure and silicon-alloyed pyrocarbons increased with increasing temperature up toabout 500°C. The room-temperature thermal conductivity of the pure carbons increased with increasing apparent crystal1it.e height (I,<), and the conductivity of the silicon-alloyed carbons was significantly lower than that of pure pyrocarbon with the same L,. The results suggest that silicon entering substitutionaliv into the carbon lattice may reduce the conductivity.