Graphite and Mica Materials
General guide to graphite and mica materials

Both of these materials are quite difficult to handle by themselves. For gasket applications these materials are usually laminated with stainless steel.

Whilst both are suitable for very high temperatures their applications are different:

Graphite
Best used where steam and process cycling is involved to provide performance superior to the standard non-asbestos jointings.
Do not use in environments over 440 centigrade in the presence of oxygen.

Mica
The classic mica application is in turbocharger gaskets.
Excellent at high temperatures but limited to pressures of a few bar.
A controlled swell version is available for use with awkward bolt loading.
Degrades in the presence of water or steam.