Properties and microstructure of molybdenum disilicide-{beta}{prime}-SiAlON particulate ceramic composites

Journal Article · Fri Oct 31 23:00:00 EST 1997 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1997.tb03201.x· OSTI ID:556437

Huang, C M; Yuh, C Y; Farooque, M ^[1]; Zhu, D; Xu, Y; Kriven, W M ^[2]

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1. Energy Research Corp., Danbury, CT (United States)
2. Univ. of Illinois, Urbana, IL (United States). Dept. of Materials Science and Engineering

Particulate ceramic composites that were composed of a combustion-synthesized {beta}{prime}-SiAlON matrix and dispersed MoSi{sub 2} particles were hot pressed at 1,600 C in a nitrogen atmosphere. The physical and mechanical properties of the composites that contained 15, 30, and 45 vol% MoSi{sub 2} were evaluated. The average four-point bend strength, fracture toughness, and Vickers hardness of the composites were in the ranges of 500--600 MPa, 3--4 MPa{center_dot}m{sup 1/2}, and 11--13 GPa, respectively. The measured mechanical strength and hardness were very similar to the values that were predicted from the rule of mixtures. The fracture toughness of the combustion-synthesized {beta}{prime}-SiAlON (2.5 MPa{center_dot}m{sup 1/2}) was apparently enhanced by the MoSi{sub 2} particles that were added. The increase in the fracture toughness was predominantly attributed to the residual thermal stress that was induced by the thermal expansion mismatch between the MoSi{sub 2} particles and the {beta}{prime}-SiAlON matrix. The composites showed improved electrical conductivity and oxidation resistance over monolithic {beta}{prime}-SiAlON. High-resolution transmission electron microscopy examination of the composites indicated that the MoSi{sub 2} was chemically well compatible with the {beta}{prime}-SiAlON.

• Sponsoring Organization: Department of the Air Force, Washington, DC (United States); USDOE, Washington, DC (United States)
• DOE Contract Number: FG02-91ER45439
• OSTI ID: 556437
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 11 Vol. 80; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
COMPOSITE MATERIALS
CONCENTRATION RATIO
ELECTRIC CONDUCTIVITY
FLEXURAL STRENGTH
FRACTURE PROPERTIES
HARDNESS
HOT PRESSING
MECHANICAL PROPERTIES
MICROSTRUCTURE
MOLYBDENUM SILICIDES
PHYSICAL PROPERTIES
SAMPLE PREPARATION
SILICON NITRIDES