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Journal of Materials Science

, Volume 25, Issue 9, pp 4113–4119 | Cite as

Surface oxidation by microwave-induced plasma of candidate composite materials for space shuttle protection

  • R. I. Ben-Aim
  • J. L. Bonardet
  • A. M. Diamy
  • J. Fraissard
  • J. C. Legrand
Papers

Abstract

Oxidation resistance of composite materials (SiC/SiC, C/SiC and C/C) which can be used to protect shuttles is studied in oxygen microwave-induced plasmas (MIP). These plasmas contain the same energetic species (electrons, ions, radicals, excited atoms or molecules) as those produced by the shock wave resulting from re-entry into the atmosphere. The plasma is sustained in a silica tube located in a resonant cavity and microwave energy is supplied by a generator operating at 2450 MHz with variable power from 15 to 1000W. Experiments are conducted at pressures from 100 to 1000 Pa with temperature ranging from 1100 to 1300 °C. The atomic oxygen flow rate is about 6.1019 at sec−1 cm−2. The wafers are exposed to the plasma for 10 to 25 h for periods of 15 or 30min. Kinetic behaviour of the material is studied by gravimetry and surface characteristic modifications are analysed by BET Krypton isotherms at 77 K and electron spectroscopy for chemical analysis (ESCA). Gravimetric results, measurements of specific surface area by krypton adsorption and ESCA analysis show that the samples of SiC/SiC and C/SiC are quite resistant to the oxygen plasma even after 25 h exposure. The mass loss is small and the specific surface area (BET) increases but is always lower than 1 m2 g−1. ESCA analysis shows that the surface evolves by change of the superficial silicon carbide into silica. The C/C samples behave quite differently: without any protection they disappear in less than 5 min. With an antioxidant protective layer, this material can be oxidation resistant. The BET and ESCA measurements show that the attack leads to a sintering of the silica which gathers on the fibres, reducing the protection of the matrix.

Keywords

Shock Wave Krypton Electron Spectroscopy Oxygen Plasma Oxygen Flow 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Chapman and Hall Ltd. 1990

Authors and Affiliations

  • R. I. Ben-Aim
    • 1
  • J. L. Bonardet
    • 1
    • 2
  • A. M. Diamy
    • 1
  • J. Fraissard
    • 1
    • 2
  • J. C. Legrand
    • 1
  1. 1.C.N.R.S. URA 870, Laboratoire de Chimie GénéraleUniversité Pierre et Marie CurieParis Cedex 05France
  2. 2.Laboratoire de Chimie des SurfacesUniversité Pierre et Marie CurieParis Cedex 05France

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