SIGRAFLEX® Expanded Natural Graphite

The unique properties of natural graphite are captured in expanded graphite for use in a variety of applications. During the expansion process, the graphite retains its excellent inherent properties such as electrical and thermal conductivity and chemical resistivity.

SGL Group markets its expanded graphite products for sealing and high-temperature applications under the well-known trade name SIGRAFLEX®. Specially developed products for energy storage are sold under the SIGRACELL® brand, those for thermal management applications under SIGRATHERM®.

Typical properties of the material

  • Flexible and soft
  • Chemically and thermally resistant
  • Highly impermeable
  • Thermaly conductive

Manufacturing of expanded graphite

Expanded graphite is manufactured from natural graphite flakes with well-ordered high-crystalline structure. When these flakes are mixed with an intercalation agent, a graphite salt forms that is then subjected to a high temperature shock treatment in which the intercalation agent escapes. During the expansion, the graphite flakes increase in volume by a factor of 200 to 400. The loose “worms” of expanded graphite are then compressed into foils and sheets without the use of any binder or filler.


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