76. The interstitial mechanism of diffusion

✍ Scribed by R.M Mayer; P.A Thrower

• Publisher: Elsevier Science
• Year: 1973
• Tongue: English
• Weight: 105 KB
• Volume: 11
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(73)90412-0

✦ Synopsis

using experimental values for the anharmonic coefficients (a&,/de,,) and (aC,,/ae,,) and allowing the coefficient (as/de,) where 6 is the bond bending coefficient to vary. The value of (as/se,,) must lie in the range 0.00 to-O.50 X 10m3 cm2/sec in order to fit experiment.

75. Thermal expansivity and thermal diffusivity of silicon-alloyed pyrocarbons

R. J. Price and K. Koyama (Gulf General Atomic Company, San Diego, California). Measurements were made of the thermal expansivity and thermal diffusivity of isotropic fluidized-bed pyrocarbons containing up to 34 wt per cent silicon. The thermal expansivities decreased with increasing silicon content and agreed with the expected values for silicon carbide-polycarbon composites. The thermal conductivities of the silicon-alloyed carbons were consistently lower than those of pure polycarbons with similar apparent crystallite heights &).