Fibrous monolithic ceramics; 4: Mechanical properties and oxidation behavior of the alumina/nickel system
- Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Materials Science and Engineering
Fibrous monolith ceramics were fabricated in the alumina/nickel system. The microstructure consists of high aspect-ratio polycrystalline cells of alumina separated by thin cell boundaries of nickel. The nickel content in the material is 3 to 8 vol%. The fibrous monolith with uniaxial aligned cells fails noncatastrophically in flexure. Bridging ligaments of nickel, crack deflection along cell boundaries, and crack branching in the axial direction are observed in flexure bars and notched beams. Strength values range from 246 to 375 MPa. Indentations cause controlled damage on the surface but do not introduce strength-degrading flaws. The alumina/nickel fibrous monoliths also show potential for use at high temperatures in oxidizing environments. Noncatastrophic fracture behavior is observed at room temperature after 10 h at 1,200 C in air. The Ni cell boundary network is oxidized to a depth of 50 to 100 [mu]m by this heat treatment. The NiO oxidation product in the cell boundaries reacts partly with alumina from the cells to form NiAl[sub 2]O[sub 4], which would provide better protection.
- OSTI ID:
- 7236281
- Journal Information:
- Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 77:5; ISSN 0002-7820; ISSN JACTAW
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360602* -- Other Materials-- Structure & Phase Studies
360603 -- Materials-- Properties
360604 -- Materials-- Corrosion
Erosion
& Degradation
ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
COMPOSITE MATERIALS
CORROSION PRODUCTS
DATA
EXPERIMENTAL DATA
FIBERS
INFORMATION
MATERIALS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NICKEL ALLOYS
NICKEL COMPOUNDS
NICKEL OXIDES
NUMERICAL DATA
OXIDATION
OXIDES
OXYGEN COMPOUNDS
TRANSITION ELEMENT COMPOUNDS