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Hydrogen-silicon carbide interactionsA study of the thermochemistry and kinetics of hydrogen environmental attack of silicon carbide was conducted for temperatures in the range from 1100 C to 1400 C. Thermodynamics maps based on the parameters of pressure and oxygen/moisture content were constructed. With increasing moisture levels, four distinct regions of attack were identified. Each region is defined by the thermodynamically stable solid phases. The theoretically stable solid phases of region 1 are silicon carbide and silicon. Experimental evidence is provided to support this thermodynamic prediction. Silicone carbide is the single stable solid phase in region 2. Active attack of the silicon carbide in this region occurs by the formation of gases of SiO, CO, CH4, SiH4 and SiH. Analyses of the kinetics of reaction for region 2 at 1300 C show the attack of the silicon carbide to be controlled by gas phase diffusion of H2O to the sample. Silicon carbide and silica are the stable phases common to regions 3 and 4. These two regions are characterized by the passive oxidation of silicon carbide and formation of a protective silica layer.
Document ID
19910044160
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Eckel, Andrew J.
(NASA Lewis Research Center Cleveland, OH, United States)
Misra, Ajay K.
(NASA Lewis Research Center Cleveland, OH, United States)
Humphrey, Donald L.
(NASA Lewis Research Center; Sverdrup Technology, Inc. Middleburg Heights, OH, United States)
Jacobson, Nathan S.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1990
Subject Category
Nonmetallic Materials
Accession Number
91A28783
Distribution Limits
Public
Copyright
Other

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