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Ultra high temperature ceramics for space and industrial applications


Transition metals (Ti, Zr, Hf, Ta) form borides and carbides that belong to a class of advanced materials defined as Ultra High Temperature Ceramics (UHTCs) for their high melting points between 3000K and 4200K.


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These materials belong a set of characteristics

  • extremely high melting point
  • high hardness
  • high electrical and thermal conductivity
  • good resistance to oxidation
  • high retained strength at high temperature

which make them unique for applications in extreme environment, especially for the aerospace:

 

  • nose cones
  • leading edges
  • control surfaces for hypersonic vehicles
  • control surfaces for re-entry vehicles
  • rocket nozzle inserts
  • air-augmented propulsion system components

 

CNR-ISTEC is the only Italian and, as far as we know, European research Institute, that is actively involved in R&D activities on UHTCs. Such R&D activities have been often supported by external contracts or within international collaborations: 

  • Italian Research Aerospace Centre
  • Italian Space Agency
  • European Space Agency
  • Department of Aerospace Engineering - University of Naples “Federico II”
  • US Air Force
  • National Science Foundation 

and include basic scientific research as well as the development of an understanding of material stability at very high temperatures in an aeroheating environment and finally the fabrication of articles and prototypes with real sizes and complex shapes.

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PUBLICATIONS & PATENTS

F.Monteverde, S. Guicciardi, A. Bellosi, Advances in microstructure and mechanical properties of ZrB2 based ceramics, Materials Science & Engineering A, 346/1-2, 310-319 (2003).

F. Monteverde, R. Savino, Stability of ultra-high temperature ZrB2-SiC ceramics under simulated atmospheric re-entry conditions, Journal of European Ceramic Society, 27, 4797-4805 (2007)

A. Bellosi, F. Monteverde, L. Scatteia, Development and properties of UHTCs for sharp leading edges on hypersonic vehicles”, Mat. Sci Engineering A, 485(1-2), 415-421 (2008).

D. Sciti, S. Guicciardi, A. Bellosi, G. Pezzotti, “Properties of a pressureless sintered ZrB2-MoSi2 ceramic composite”, Journal of the American Ceramic Society, 89 [7] 2320-2322 (2006)

S. Guicciardi, L. Silvestroni, M. Nygren, D. Sciti, “Microstructure and toughening mechanisms in spark plasma sintered ZrB2 Ceramics reinforced by SiC Whiskers or SiC chopped fibers”, Journal of the American Ceramic Society, 93 [8] 2384-2391(2010).

PROCESSES & FACILITIES

The R&D activities involve a logical sequence:

  • Compositional Design
  • Fabrication of Materials
  • Thermo-mechanical characterization
  • Manufacturing of prototypes

in order to define novel ultra-refractory materials suitable for high-temperature applications as well as to identify correlation between key properties and microstructure.

  • Compositional design: selection of type and quantity of some transition metal borides or carbides and other second phases (SiC particles or fibers, metal silicides)
  • Powder processing: mixing-milling-drying
  • Forming of “green” bodies and sintering using special high temperature furnaces (hot pressing, gas pressure sintering up to 2150°C in inert atmosphere).

 

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The as-sintererd materials are then characterized

  • microstructure (XRD, SEM-EDX, TEM)
  • thermo-mechanical properties (hardness, elastic modulus, flexural strength, fracture toughness, thermal expansion, thermal shock resistance, thermal conductivity)
  • resistance to oxidation 
  • dynamic resistance to oxidation in aero-heating environment (in collaboration with DIAS –University of Naples “Federico II”)

Small articles or larger prototypes are designed and fabricated on specific requests.

MAIN SCIENTIFIC COLLABORATIONS:

  • 2004: PRORA-USV-UHTC “Nose Cap-Massive Diborides (Italian Aerospace Research Centre)
  • 2008-2009: Advanced Structure Assembly – Phase B (Italian Space Agency)
  • 2008-2009: DEDALO, Ultra High temperature Ceramics (Lombardia District)
  • 2008-2010: Development and characterization of UHTCs (Bilateral Project CNR of Italy – Chinese Academy of Sciences) 
  • 2009: In-flight aerothermodynamic characterization of ultra-high temperature ceramics (European Space Agency)
  • 2010-2011: Toughened massive UHTCs (Italian Aerospace Research Centre)
  • 2010-2011: Oxidation tests of UHTC using solar furnace (PROMES-CNRS, France)
  • 2009-2010: Characterization of UHTC through transmission electron microscopy (FA8655-09-M-4002, European Office of Aerospace Research and Development- UK, US Air Force
  • 2010-2012: UHTCs with high mechanical strength and toughness reinforced by fibers and CNTs (Bilateral Project CNR of Italy –Slovak Academy of Sciences)