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Reactions of Silicon‐Based Ceramics in Mixed Oxidation Chlorination Environments
Author(s) -
MARRA JOHN E.,
KREIDLER ERIC R.,
JACOBSON NATHAN S.,
FOX DENNIS S.
Publication year - 1988
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1988.tb05793.x
Subject(s) - silicon , chlorine , materials science , ceramic , analytical chemistry (journal) , limiting , inorganic chemistry , corrosion , partial pressure , penetration (warfare) , chemical engineering , chemistry , mineralogy , metallurgy , oxygen , organic chemistry , mechanical engineering , engineering , operations research
The reaction of silicon‐based ceramics with 2% Cl 2 /Ar and 1% Cl 2 /1% to 20% O 2 /Ar at 950 °C was studied with thermogravimetric analysis and high‐pressure mass spectrometry. Pure Si, SiO 2 , several types of SiC, and Si 3 N 4 were examined. The primary corrosion products were SiCl 4 ( g ) and SiO 2 ( s ) with smaller amounts of volatile silicon oxychlorides. The reactions appear to occur by chlorine penetration of the SiO 2 layer, and gas‐phase diffusion of the silicon chlorides away from the sample appears to be rate limiting. Pure SiO 2 shows very little reaction with Cl 2 . SiC with excess Si is more reactive than the other materials with Cl 2 , whereas SiC with excess carbon is more reactive than the other materials with Cl 2 /O 2 . Si 3 N 4 shows very little reaction with Cl 2 . These diferences are explained on the basis of thermodynamic and microstructural factors.