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Accession Number N20120012575
Title Vapor Pressure and Evaporation Coefficient of Silicon Monoxide over a Mixture of Silicon and Silica.
Publication Date Jan 2012
Media Count 8p
Personal Author F. T. Ferguson J. A. Nuth
Abstract The evaporation coefficient and equilibrium vapor pressure of silicon monoxide over a mixture of silicon and vitreous silica have been studied over the temperature range (1433 to 1608) K. The evaporation coefficient for this temperature range was (0.007 plus or minus 0.002) and is approximately an order of magnitude lower than the evaporation coefficient over amorphous silicon monoxide powder and in general agreement with previous measurements of this quantity. The enthalpy of reaction at 298.15 K for this reaction was calculated via second and third law analyses as (355 plus or minus 25) kJ per mol and (363.6 plus or minus 4.1) kJ per mol respectively. In comparison with previous work with the evaporation of amorphous silicon monoxide powder as well as other experimental measurements of the vapor pressure of silicon monoxide gas over mixtures of silicon and silica, these systems all tend to give similar equilibrium vapor pressures when the evaporation coefficient is correctly taken into account. This provides further evidence that amorphous silicon monoxide is an intimate mixture of small domains of silicon and silica and not strictly a true compound.
Keywords Chemical reactions
Crystal growth
Knudsen flow
Silicon dioxide
Single crystals
Temperature distribution
Vapor pressure
Vitreous materials

Source Agency National Aeronautics and Space Administration
NTIS Subject Category 99 - Chemistry
Corporate Author Goddard Space Flight Center, Greenbelt, MD.
Document Type Journal article
Title Note N/A
NTIS Issue Number 1303
Contract Number N/A

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