Kinetics and mechanisms of oxidation of 2D woven C/SiC composites; 1: Experimental approach
- UMR 47, Pessac (France). Lab. des Composites Thermostructuraux
- Societe Europeenne de Propulsion, Saint Medard-en-Jalles (France)
The oxidation behavior of a 2D woven C/SiC composite partly protected with a SiC seal coating and heat-treated (stabilized) at 1,600 C in inert gas has been investigated through an experimental approach based on thermogravimetric analyses and optical/electron microscopy. Results of the tests, performed under flowing oxygen, have shown that the oxidation behavior of the composite material in terms of oxidation kinetics and morphological evolutions is related to the presence of thermal microcracks in the seal coating as well as in the matrix. Three different temperature domains exist. At low temperatures (< 800 C), the mechanisms of reaction between carbon and oxygen control the oxidation kinetics and are associated with a uniform degradation of the carbon reinforcement. At intermediate temperatures, (between 800 and 1,100 C), the oxidation kinetics are controlled by the gas-phase diffusion through a network of microcracks in the SiC coatings, resulting in a nonuniform degradation of the carbon phases. At high temperatures (> 1,100 C), such diffusion mechanisms are limited by sealing of the microcracks by silica; therefore, the degradation of the composite remains superficial. The study of the oxidation behavior of (i) the heat-treated composite in a lower oxygen content environment (dry air) and (ii) the as-processed (unstabilized) composite in dry oxygen confirms the different mechanisms proposed to explain the oxidation behavior of the composite material.
- OSTI ID:
- 6887135
- Journal Information:
- Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 77:8; ISSN 0002-7820; ISSN JACTAW
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360604* -- Materials-- Corrosion
Erosion
& Degradation
CARBIDES
CARBON COMPOUNDS
CARBON FIBERS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COATINGS
COMPOSITE MATERIALS
DATA
EXPERIMENTAL DATA
FIBERS
HEAT TREATMENTS
INFORMATION
KINETICS
MATERIALS
MORPHOLOGY
NUMERICAL DATA
OXIDATION
PROTECTIVE COATINGS
REACTION KINETICS
SILICON CARBIDES
SILICON COMPOUNDS