KNL Expandable graphite, what do we know about it, page-19

https://www.sglgroup.com/cms/intern...of-materials/index.html?letter=E&__locale=en#



Expanded natural graphite
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The Material

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 electrical and thermal conductivity.



The Properties

• flexible and soft
• chemically and thermally resistant
• high impermeability
• high thermal conductivity

The Manufacturing Process

Expanded graphite is manufactured from natural graphite flakes with well-ordered high-crystalline structures. When these flakes are mixed with an intercalation agent, a graphite salt forms which is then subjected to a high temperature shock. During the expansion, the graphite flakes increase in volume by a factor of 200 to 400. The loose “worms” of expanded graphite are compressed without any binding or fillers into products such as sheets or foils.





Expansion process:




In the left photo we can see individual flakes stacked on top of each other .

A single flake can be expanded by the process described above in to expanded
graphite increasing it's thickness by 200 to 400 times ,

On the right hand you see the a opened flake which looks a bit like concertina door .

And yes heat is a very important factor in the graphite creation !