In-Situ Processing and Characterization of Mosi2/Sic Formed by Reactive Low-Pressure Plasma Deposition

AbstractLow-pressure plasma deposition (LPPD) was used to synthesize an in-situ MoSi2/SiC composite using 100% methane (CH4) as a powder carrier gas. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) identified MoSi2, Mo5Si3, Mo5Si3C, Si02, and SiC as the phases present in the composite. XRD and XPS revealed ∼6 vol% SiC in the as-sprayed material. Annealing of the as-sprayed composite increased the SiC content to ∼8 vol% while reducing the Si02 volume fraction. Transmission electron microscopy studies revealed a fine homogeneous distribution of SiC and/or carbide particles at prior splat boundaries in the MoSi2 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 m½ for annealed composites. The creep behavior of the LPPD reactive spray composite dramatically improved compared to unreinforced LPPD MoSi2. Additionally, the creep behavior was shown to be equal to or better than that of powder metallurgy MoSi2/SiC composites containing higher percentages of SiC.

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Synthesis and Properties of MoSi2/SiC Processed by Low Pressure Plasma Co-Injection and Deposition

MRS Proceedings ◽

10.1557/proc-322-139 ◽

1993 ◽

Vol 322 ◽

Cited By ~ 2

Author(s):

D.E. Lawrynowicz ◽

J. Wolfenstine ◽

S. Nutt ◽

E.J. Lavernia ◽

D.E. Bailey ◽

...

Keyword(s):

Electron Microscopy ◽

Volume Fraction ◽

Plasma Deposition ◽

Low Pressure ◽

High Concentration ◽

Pressure Plasma ◽

Alternative Processing ◽

Transmission Electron ◽

Low Pressure Plasma ◽

Sic Composites

AbstractLow-pressure plasma deposition (LPPD) and co-injection has been used to fabricate a MoSi2 composite reinforced with 15 µm SiC particles. The microstructure and creep behavior of the LPPD processed composite are reported and discussed. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed the structure of the composite to be lamellar and energy dispersive X-ray analysis (EDAX) identified the phases present in the material as: MoSi2, Mo5Si3, SiO2, and SiC. Density characterization revealed a porosity of less than 1.0 vol. %, indicating a nearly fully dense material. A high concentration of SiO2 (∼8.0 vol. %) present in the MoSi2/SiC composite may be attributed to possible contamination of the starting powders before or during LPPD. Sublimation of SiC during co-injection led to a low volume fraction (< 2.0 vol. %) of reinforcement in the composite. The creep rate of the LPPD MoSi2/SiC was higher relative to that of MoSi2/SiC composites fabricated by powder metallurgy (PM) techniques. On the basis of the results of this study it has become evident that alternative processing methods such as LPPD insitu processing may be better suited for the fabrication of elevated volume fraction MoSi2/SiC composites.

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Rapid Solidification by Plasma Deposition

MRS Proceedings ◽

10.1557/proc-30-91 ◽

1983 ◽

Vol 30 ◽

Cited By ~ 1

Author(s):

D. Apelian

Keyword(s):

Rapid Solidification ◽

Plasma Deposition ◽

Low Pressure ◽

Structural Refinement ◽

Pressure Plasma ◽

Low Pressure Plasma ◽

Solidification Processes

ABSTRACTRapid solidification processes (RSP) have been reviewed. The structural refinement one may obtain via RSP and the consolidation methods which need to be utilized have also been reviewed. The merits of low pressure plasma deposition (LPPD) or rapid solidification by plasma deposition (RSPD) as a means of combining both the atomization and consolidation steps of RSP is highlighted. The applications and challenges of RSPD are discussed.

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Low-pressure plasma deposition of tungsten

Journal of Thermal Spray Technology ◽

10.1007/bf02648270 ◽

1994 ◽

Vol 3 (2) ◽

pp. 135-141 ◽

Cited By ~ 5

Author(s):

W. Cai ◽

H. Liu ◽

A. Sickinger ◽

E. Muehlberger ◽

D. Bailey ◽

...

Keyword(s):

Plasma Deposition ◽

Low Pressure ◽

Pressure Plasma ◽

Low Pressure Plasma

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Production of Composite Structures by Low-Pressure Plasma Deposition

Proceedings of the 9th Annual Conference on Composites and Advanced Ceramic Materials: Ceramic Engineering and Science Proceedings, Volume 6, Issue 7/8 - Ceramic Engineering and Science Proceedings ◽

10.1002/9780470320280.ch43 ◽

2008 ◽

pp. 896-907 ◽

Cited By ~ 9

Author(s):

P. A. Siemers ◽

M. R. Jackson ◽

R. L. Mehan ◽

J. R. Rairden

Keyword(s):

Composite Structures ◽

Plasma Deposition ◽

Low Pressure ◽

Pressure Plasma ◽

Low Pressure Plasma

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Functionalization of Neutral Polypropylene by Using Low Pressure Plasma Treatment: Effects on Surface Characteristics and Adhesion Properties

Polymers ◽

10.3390/polym11020202 ◽

2019 ◽

Vol 11 (2) ◽

pp. 202 ◽

Cited By ~ 10

Author(s):

Chiara Mandolfino ◽

Enrico Lertora ◽

Carla Gambaro ◽

Marco Pizzorni

Keyword(s):

Surface Morphology ◽

Photoelectron Spectroscopy ◽

Polymeric Materials ◽

Low Pressure ◽

Contact Angles ◽

Bonded Joints ◽

Water Contact ◽

Adhesion Properties ◽

Pressure Plasma ◽

Low Pressure Plasma

Polyolefins are considered among the most difficult polymeric materials to treat because they have poor adhesive properties and high chemical barrier responses. In this paper, an in-depth study is reported for the low pressure plasma (LPP) treatment of neutral polypropylene to improve adhesion properties. Changes in wettability, chemical species, surface morphology and roughness of the polypropylene surfaces were evaluated by water contact angle measurement, X-ray photoelectron spectroscopy and, furthermore, atomic force microscopy (AFM). Finally, the bonded joints were subjected to tensile tests, in order to evaluate the practical effect of changes in adhesion properties. The results indicate that plasma is an effective treatment for the surface preparation of polypropylene for the creation of bonded joints: contact angles decreased significantly depending on the plasma-parameter setup, surface morphology was also found to vary with plasma power, exposure time and working gas.

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