No abstract

The surface growth rate of soot increases steeply with increasing equivalence ratio. We have found that the increased growth rate is accounted for primarily by the increased surface area available for growth rather than by increased concentrations of surface growth species. We have shown thai the surface growth species are not depleted by the process of surface growth. Our data suggest that the surface growth seen in our flames can be accounted for primarily by reaction of acetylene with the soot particles.

We have measured mole fractions of two of the major stable species at the surface of a silicon substrate during filament-assisted diamond growth as a function of the filament-to-substrate distance. Input gases were methane and hydrogen. A quartz probe withdrew gases at the growing surface, and the gases were sampled with an on-line mass spectrometer. Close to the filament the methane is largely consumed, with most of the remaining gas phase carbon in the form of acetylene. Mass spectral results are compared to compositions calculated with a detailed chemical kinetics model. Our initial analysis suggests that diamond growth comes mainly from reaction of acetylene, ethylene, methane, or methyl radical.

Hardness and Young's modulus of high-quality cubic boron nitride films grown by chemical vapor deposition

No abstract