Interfaces in silicon-carbide whisker-reinforced silicon-nitride-based composites: A high-resolution electron-microscopy study

Thesis/Dissertation · Mon Dec 31 23:00:00 EST 1990

OSTI ID:7110475

Das Chowdhury, K

Four kinds of silicon nitride/silicon carbide (whisker) matrix composites synthesized from common starting materials, except the whiskers themselves, at the same processing conditions were investigated. The interfacial structure and chemistry of the existence of an interfacial layer at the interface will affect the mechanical properties of the composites, e.g., crack propagation under applied stress, profoundly. The chemical environment near the interface will change the local elastic moduli and flow stress and eventually the fracture toughness of the composite. High-resolution electron-imaging microscopy and high-spatial-resolution electron energy-loss nanospectroscopy were used to characterize the whisker/matrix and matrix grain-boundary interfaces in these composites both structurally and chemically. The presence of a 1.5 to 2 nm-wide discontinuous oxygen-rich amorphous layer at the four kinds of whisker/matrix interfaces and 0.5 to 2 nm-wide continuous oxygen-rich and nitrogen-depleted amorphous layer at the matrix grain-boundary interfaces examined appeared to be general phenomena.

• Research Organization: Arizona State Univ., Tempe, AZ (United States)
• OSTI ID: 7110475
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
CARBIDES
CARBON COMPOUNDS
COMPOSITE MATERIALS
CRYSTALS
ELECTRON MICROSCOPY
INTERFACES
MATERIALS
MATRIX MATERIALS
MICROSCOPY
MONOCRYSTALS
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
SILICON CARBIDES
SILICON COMPOUNDS
SILICON NITRIDES
WHISKERS