Strength of nicalon silicon carbide fibers exposed to high-temperature gaseous environments

Journal Article · Fri Mar 01 04:00:00 EST 1991 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1991.tb04079.x· OSTI ID:5161745

Kim, H E; Moorhead, A J ^[1]

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1. Metals and Ceramics Div., Oak Ridge National Lab., Oak Ridge, TN (US)

The effects of exposures to high-temperature gaseous atmospheres on the strength of Nicalon SiC fibers were investigated. The exposure conditions were as follows: (1) H{sub 2} with various P{sub H{sub 2}O} for 10 h at 1000{degrees} and 1200{degrees}C, and (2) air for 2 to 100 h at 800{degrees} to 1400{degrees}C. Individual fibers were tested in tension following each exposure. The strengths of the fibers were strongly influenced by exposure atmosphere and temperature, but less affected by time at temperature. When exposed in air, a SiO{sub 2} layer was formed on the surface, minimizing the degradation of strength. However, this beneficial effect was negated under conditions in which the SiO{sub 2} layer became too thick. The most severe degradation resulted from exposure to a reducing atmosphere, presumably due to the reduction of SiO{sub 2} inherent in the fibers.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5161745
• Journal Information: Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 74:3; ISSN 0002-7820; ISSN JACTA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
ATMOSPHERES
CARBIDES
CARBON COMPOUNDS
CONTROLLED ATMOSPHERES
FLUIDS
FRACTURE PROPERTIES
GASES
HIGH TEMPERATURE
MATERIALS TESTING
MECHANICAL PROPERTIES
NONDESTRUCTIVE TESTING
SILICON CARBIDES
SILICON COMPOUNDS
TESTING
THERMAL DEGRADATION
THERMAL TESTING