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U.S. Department of Energy
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Effects of chlorine and alkali chlorides on corrosion of silicon carbide based ceramics in combustion environments. Topical report, June 1, 1987-May 31, 1992

Technical Report ·
OSTI ID:147497
High temperature corrosion of SiC based ceramics in oxidizing gas mixtures containing chlorine and chloride compounds has been characterized. SiC based ceramics can be subject to rapid active oxidation in gases where the ratio of chlorine to oxygen is greater than one. A passive film will form at sufficiently high temperatures or oxygen contents. The conditions under which a passive film forms are affected by the sintering aids used in the manufacture of the ceramic. Silicon nitride is resistant to this type of attack, but the silicon nitride in nitride bonded SiC does not protect the SiC grains in this material. At temperatures above 1200 deg. C, oxidation of SiC can be accelerated by penetration of chlorine containing environments, the alkali produces the attack by fluxing the silica film to liquid alkali silicate. This type of attack is accelerated by water vapor and inhibited by HC1 or chlorine.
Research Organization:
Pennsylvania State Univ., University Park, PA (United States). Center for Advanced Materials
OSTI ID:
147497
Report Number(s):
PB--96-107354/XAB; CAM--9413; CNN: Contract GRI-5084-238-1302
Country of Publication:
United States
Language:
English