Actions for Oxidation of SiC Fiber-Reinforced SiC Matrix Composites with a BN Interphase

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Oxidation of SiC Fiber-Reinforced SiC Matrix Composites with a BN Interphase

Author
Boyd, Meredith K.
Published
May 05, 2010.
Physical Description
1 electronic document
Additional Creators
Opila, Elizabeth
Online Version

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Summary
SiC-fiber reinforced SiC matrix composites with a BN interphase were oxidized in reduced oxygen partial pressures of oxygen to simulate the environment for hypersonic vehicle leading edge applications. The constituent fibers as well as composite coupons were oxidized in oxygen partial pressures ranging from 1000 ppm O2 to 5% O2 balance argon. Exposure temperatures ranged from 816 C to 1353 C (1500 F to 2450 F). The oxidation kinetics of the coated fibers were monitored by thermogravimetric analysis (TGA). An initial rapid transient weight gain was observed followed by parabolic kinetics. Possible mechanisms for the transient oxidation are discussed. One edge of the composite coupon seal coat was ground off to simulate damage to the composite which allowed oxygen ingress to the interior of the composite. Oxidation kinetics of the coupons were characterized by scanning electron microscopy since the weight changes were minimal. It was found that sealing of the coupon edge by silica formation occurred. Differences in the amount and morphology of the sealing silica as a function of time, temperature and oxygen partial pressure are discussed. Implications for use of these materials for hypersonic vehicle leading edge materials are summarized.
Other Subject(s)
Collection
NASA Technical Reports Server (NTRS) Collection.
Note
Document ID: 20100040692.
E-17511.
8thSpring Meeting of the International Society of Electrochemistry; 5 May 2010; Columbus, OH; United States.
Terms of Use and Reproduction
Copyright, Distribution as joint owner in the copyright.
View MARC record | catkey: 15993299