Ultrasonic characterization of oxidation mechanisms in Nicalon/C/SiC composites

Journal Article · Sat Oct 01 00:00:00 EDT 1994 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1994.tb04642.x· OSTI ID:6765007

Huger, M; Fargeot, D; Gault, C ^[1]

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1. Lab. Materiaux Ceramiques et Traitements de Surface, Limoges (France)

The nonbrittle fracture of composites consisting of ex poly-carbosilane SiC (Nicalon) fibers in a SiC matrix prepared by chemical vapor infiltration is strongly dependent on the presence of a pyrocarbon layer at the fiber/matrix interface (Nicalon/C/SiC composites). The mechanical properties of such materials are known to be influenced by oxidation reactions. Elastic modulus measurements, using ultrasonic wave propagation in the ''long bar'' mode, have been used to show the influence of the environmental parameters temperature, atmosphere, and pressure on the mechanical behavior of bidirectional Nicalon/C/SiC. In situ measurements of elastic modulus performed in parallel with thermogravimetric analysis allow examination of oxidation mechanisms which affect interfacial properties. Results showed the modulus to be affected by two interfacial oxidation mechanisms: (1) oxidation of pyrocarbon coating and (2) closure of the resulting interphase gap by silica formation.

• OSTI ID: 6765007
• Journal Information: Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 77:10; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603 -- Materials-- Properties
360604* -- Materials-- Corrosion
Erosion
& Degradation
CARBIDES
CARBON
CARBON COMPOUNDS
CHEMICAL REACTIONS
COMPOSITE MATERIALS
DATA
ELEMENTS
EXPERIMENTAL DATA
INFORMATION
INTERFACES
MATERIALS
MECHANICAL PROPERTIES
NONMETALS
NUMERICAL DATA
OXIDATION
PRESSURE DEPENDENCE
SILICON CARBIDES
SILICON COMPOUNDS
TEMPERATURE DEPENDENCE
YOUNG MODULUS