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CCVD Technology and Traditional Coating Technologies
Thin films have traditionally been deposited using CVD, PVD, or
Sol-gel. Existing CVD and PVD technologies require a reaction or
vacuum chamber to deposit thin films. Traditionally, CVD also
requires a furnace or auxiliary heating system to further control
the environment for the deposition to occur. Due to these
temperature and vacuum requirements, substrates (the materials being
coated) that can be used in these processes are limited. Sol-gel
requires multiple deposition steps to achieve acceptable thin film
thickness, with concurrent difficulties in maintaining the purity of
the resultant thin film.
Traditional Coating Technologies
Technology |
Issues |
Chemical Vapor Deposition (CVD) |
- Difficult or impossible to deposit multi-element compounds
- Requires expensive high temperature reaction furnace and/or vacuum environment, and expensive high vapor pressure compounds
- Substrate must withstand high temperatures (limits choices)
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Physical Vapor Deposition (PVD) |
- Difficult or impossible to deposit multi-element compounds
- Requires expensive high vacuum chamber
- Substrate must be vacuum compatible (limits choices)
- Limited to flat substrates
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Sol-gel |
- Difficult to maintain purity
- Multi-step process (lower productivity)
- High temperature substrates only
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nGimat's proprietary Combustion Chemical Vapor Deposition (CCVD)
process is an open-atmosphere, flame-based technique for depositing
high-quality thin films and nanomaterials. A schematic
representation of a CCVD system for thin film coatings and its major
components is shown below compared to a traditional CVD
system.
The CCVD process is based on nGimat's NanoSpray
Combustion Processing technology. In the process, precursors
(metal-bearing chemicals used to coat an object) are first dissolved
in a solution, which typically is a combustible fuel. This solution
is then atomized to form microscopic droplets by means of nGimat's
proprietary Nanomiser®
Device. These droplets are next carried by an oxygen stream to
the flame where they are combusted. A substrate (the material being
coated) is coated by simply drawing it in front of the flame. The
heat from the flame provides the energy required to vaporize the
droplets and for the precursors to react and deposit on the
substrate. One of the strengths of the CCVD process is the variety
of deposited materials and substrates that
can be utilized. The CCVD process offers significant advantages over
traditional CVD/PVD techniques, including:
- Quality production of highly-tailored and complex material
solutions that cannot be commercially achieved with CVD/PVD
processes;
- Elimination of energy intensive, highly specialized and
expensive equipment (e.g., vacuum chambers, reaction furnaces and
chemical scrubbers);
- Continuous manufacturing capability currently unavailable
under competing CVD/PVD batch technologies; and
- Use of low-cost and environmentally friendly precursors and
other process chemicals.
Deposited Materials
This is a representative, but not complete, list of deposited materials, substrates and application areas. Many of these same materials can be deposited as nanopowders desired for any number of applications.
Metals |
Ceramics |
Others |
Ag, Au, Cu, Ir, Ni, Rh, Pt, Ru, Zn |
Al2O3, Al2O3•MgO, 3Al2O3•2SiO2, BaCeO3, BaCO3, BaTiO3,
BST, doped-CeO2, Cr2O3, CuxO, [La.95Ca.05]CrO3,
Fe2O3, In2O3, ITO, LaAlO3, LaPO4,
LSC, LSM, MgO, Mn2O3, MoO3, Nb2O5, NiO, NSM,
PbSO4, PbTiO3, PdO, PLZT, PMN,
PMT, PNZT, PZT, RbOx, RhOx, RuO2, SiO2, Spinels (e.g. NiAl2O4, NiCr2O4),
Silica Glasses, SnO2, SrLaAlO4, SrRuO3, SrTiO3, Ta2O5, TiO2, V2O5,
WO3, YBa2Cu3Ox, YbBa2Cu3Ox,
YIG, YSZ, YSZ•Al2O3, YSZ-Ni, ZrO2, ZnO (+ dopants in many cases) |
Over 10 polymers (polyimides, NafionTM, epoxies), numerous composites of metals, ceramics and polymers |
Substrates Used |
Al, Brass, Ag, Cu, Pt, Ni, Stainless and C-Steel,
Al2O3, Fiber Tows, Glass, Graphite, LaAlO3, MgO,
NafionTM, NiCr, Optical fibers, OPP, PET,
Polycarbonate, Silica, Si, Si-Ti/Pt wafers, SiC, Si3N4, Superalloys,
TeflonTM, Ti, TiAl alloy, YSZ, powders |
Some Applications |
Adhesion, capacitors, catalytic
applications, corrosion resistance, gas diffusion barriers,
electronics, engines, ferroelectric materials, flat panel
displays, fuel cells, interface layers, optics, piezoelectrics,
resistors, RF and millimeter wave components solar cells,
superconductors, thermal barrier, thermal control, and wear
resistance |
For additional CCVD technical information, refer to:
- Hunt, A.T., et al. (1993, July 12). Combustion chemical vapor deposition: A novel thin-film deposition technique.
Applied Physics Letters, pp. 266-268.
- Hunt, A.T., et al., Method and Apparatus for the Combustion Chemical Vapor Deposition of Films and Coatings, U.S.
Patent 5,652,021, 1997.
- Hunt, A.T., et al., Combustion Chemical Vapor Deposition of Phosphate Films and Coatings, U.S.
Patent 5,858,465, 1999.
- Hunt, A.T., et al., Method for the Combustion Chemical Vapor Deposition of Films and Coatings, U.S.
Patent 6,013,318, 2000.
- Hunt, A.T., Pohl, M. (2001). Combustion Chemical Vapor Deposition (CCVD). In Park, J. (ed.),
Chemical Vapor Deposition (pp. 81-102). Materials Park, Ohio: ASM International.
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