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

abstract

  • 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 m 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.

published proceedings

  • MRS Advances

author list (cited authors)

  • Lawrynowicz, D. E., Wolfenstine, J., Lavernia, E. J., Nutt, S. R., Bailey, D. E., Sickinger, A., & Hirt, A. M.

complete list of authors

  • Lawrynowicz, DE||Wolfenstine, J||Lavernia, EJ||Nutt, SR||Bailey, DE||Sickinger, A||Hirt, AM

publication date

  • 1994