Coatings and surface modification of carbon based materials

Combining carbon components with different coating systems successfully brings together two disciplines that, in the past, have often been treated separately.  The broad material and product know-how of the SGL Group, combined with the coating know-how of internal and external partners, can unleash considerable untapped potential. SiC coatings for semiconductor, LED, and photovoltaic applications are already state of the art at SGL Group.

In addition, we are continually expanding our knowledge of different ceramic, metal or carbon based coating systems for our materials, together with our partners, in the field of chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma coatings, electroless deposition, etc. This enables the improvement and optimization of existing products, as well as the creation of entirely new combinations of properties for new applications.

Potential applications for carbon based materials with coatings are opening up, among other things, in the fields of:

  • Friction reduction / adjustment
  • Wear protection
  • Protection against oxidation and corrosion
  • Gastightness
  • Electrical / thermal contact
  • Adjustment of the surface energy, wettability, etc.
  • Aesthetics and texture/feel

Nickel and copper coating of carbon fibers and graphite, with adjustable coating thickness

Scanning electron microscope (SEM)
image of a nickel coated
carbon fiber filament
Copper coated
carbon fiber bundle
SEM image
of nickel coated graphite

Various metals can be deposited electrolessly (chemically) on a wide variety of substrates. Electroless deposition enables the coating of non-conductive substrates. In addition, the influence of an electric field during the coating, and thus an irregular layer thickness at edges and corners, is eliminated.

The coating of carbon fibers and graphite materials with nickel and copper are examples of a successful adaptation of electroless deposition for carbon based materials. In doing so, a metallic coating can be applied, such as for electrical contact, as corrosion protection, etc. In the fiber sector, it is possible to use a metallic coating as an interface for new composite materials, e.g. metal matrix composites (MMC).

Depending on the intended application, a number of additional metallic coating systems are conceivable.

Pyrolytically Deposited Carbon (PyC) – Coating on Graphite

Light microscope image of PyC on fine grain graphite

Gas phase deposition and gas phase infiltration of carbon to produce pyrolytic carbon (PyC) has been used for a number of purposes over many years. Areas of application include coatings in the nuclear, or other industrial sector, where a gastight carbon layer is required. In addition, PyC is used as an infiltration material to densify porous carbon bodies. Examples of use are aircraft brake discs, heat shields or carbon based melting crucibles. The combination of chemical resistance and impermeability to the process media makes pyrolytically deposited carbon coatings very attractive for applications in chemical process equipment.

 

The material carbon is already an integral part of many products across different industries. The surface refinement of carbon based products opens up even more potential areas of application and broadens the horizon - also for you!

What ideas would you like to implement? What will make your products unique in the future? If you are convinced of the intrinsic value of carbon, and can see the potential in developing a surface finish, then get in touch with us! We look forward to assist you in implementing your ideas.

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