Reactive synthesis and characterization of MoSi[sub 2]/SiC using low-pressure plasma deposition and 100% methane

Journal Article · Wed Mar 01 00:00:00 EST 1995 · Scripta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-716X(95)91587-F· OSTI ID:6871093

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
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) of MoSi[sub 2] using 100% methane as a reactive powder carrier yielded a material with [approximately] 6 vol. % SiC, [approximately]6 vol.% SiO[sub 2] and [approximately]13 vol.% Mo[sub 5]Si[sub 3] and Mo[sub 5]Si[sub 3]C. The SiC phase formed during reactive spraying was cubic ([beta]-SiC) and exhibited a particulate morphology. The majority of the SiC particles were submicron in size and tended to be located at prior droplet boundaries. The SiO[sub 2] phase was along prior droplet boundaries. The Mo[sub 5]Si[sub 3] and Mo[sub 5]Si[sub 3]C phases were dispersed as particles within a MoSi[sub 2] lamella. In addition, a substantial amount of elemental carbon was observed in the as sprayed material. The volume fraction of SiC observed in the reactive plasma-sprayed MoSi[sub 2] is higher than that typically obtained using blended powders or co-injection. Annealing of the as-sprayed material increased the amount of SiC to [approximately]8 vol.% and decreased the amount of SiO[sub 2] and elemental carbon. The room temperature fracture toughness of the as sprayed material was [approximately]7 MPa m[sup 1/2]. Annealing caused the fracture toughness to increase on the order of [approximately]10 MPa m[sup 1/2]. This value is higher than that typically obtained for MoSi[sub 2]/SiC composites processed by other methods.

• OSTI ID: 6871093
• Journal Information: Scripta Metallurgica et Materialia; (United States), Vol. 32:5; ISSN 0956-716X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
PLASMA ARC SPRAYING
MOLYBDENUM SILICIDES
SILICON CARBIDES
CARBON
FRACTURE PROPERTIES
MECHANICAL PROPERTIES
METHANE
MICROSTRUCTURE
SILICON OXIDES
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY
ALKANES
CARBIDES
CARBON COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
DEPOSITION
DIFFRACTION
ELECTRON MICROSCOPY
ELEMENTS
HYDROCARBONS
MATERIALS
MICROSCOPY
MOLYBDENUM COMPOUNDS
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
SCATTERING
SILICIDES
SILICON COMPOUNDS
SPECTROSCOPY
SPRAY COATING
SURFACE COATING
TRANSITION ELEMENT COMPOUNDS
360601* - Other Materials- Preparation & Manufacture