In-situ processing and characterization of MoSi{sub 2}/SiC formed by reactive low-pressure plasma deposition

Book · Sat Jul 01 04:00:00 EDT 1995

OSTI ID:72496

Lawrynowicz, D E; Wolfenstine, J; Lavernia, E J ^[1]; Nutt, S R ^[2]; Bailey, D E; Sickinger, A ^[3]; Hirt, A M ^[4]

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1. Univ. of California, Irvine, CA (United States). Materials Science and Engineering Dept.
2. Univ. of Southern California, Los Angeles, CA (United States). Materials Science Dept.
3. Electro-Plasma, Inc., Irvine, CA (United States)
4. Materials Research Labs., Inc., Struthers, OH (United States)

Low-pressure plasma deposition (LPPD) was used to synthesize an in-situ MoSi{sub 2}/SiC composite using 100% methane (CH{sub 4}) as a powder carrier gas. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) identified MoSi{sub 2}, Mo{sub 5}Si{sub 3}, Mo{sub 5}Si{sub 3}C, SiO{sub 2}, and SiC as the phases present in the composite. XRD and XPS revealed {approximately}6 vol% SiC in the as-sprayed material. Annealing of the as-sprayed composite increased the SiC content to {approximately}8 vol% while reducing the SiO{sub 2} volume fraction. Transmission electron microscopy studies revealed a fine homogeneous distribution of SiC and/or carbide particles at prior splat boundaries in the MoSi{sub 2} matrix. Wavelength dispersive spectroscopy (WDS) confirmed the increased presence of carbon in the in situ materials. Fracture toughness measurements yielded values on the order of 10 MPa m{sup 1/2} for annealed composites. The creep behavior of the LPPD reactive spray composite dramatically improved compared to unreinforced LPPD MoSi{sub 2}. Additionally, the creep behavior was shown to be equal to or better than that of powder metallurgy MoSi{sub 2}/SiC composites containing higher percentages of SiC.

• OSTI ID: 72496
• Report Number(s): CONF-941144--; ISBN 1-55899-265-0
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPARATIVE EVALUATIONS
COMPOSITE MATERIALS
EXPERIMENTAL DATA
FRACTURE PROPERTIES
HEAT RESISTANT MATERIALS
INTERMETALLIC COMPOUNDS
MECHANICAL PROPERTIES
MICROSTRUCTURE
MOLYBDENUM SILICIDES
PLASMA ARC SPRAYING
SILICON CARBIDES