Quote:
Originally posted by bigben2k
Joe is right.
I'm looking at an add right now from graftech.com, and they're showing off their eGraf HS-400 material.
Thermal conductivity (in-plane): 370 W/mK
Thermal conductivity (thickness): 6.5 W/mK
Density: 1.94 g/cm^3 (lighter than aluminium)
Heat capacity: 846 J/kgK (Alu is 900, copper is 380)
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Graphite has a layered cristalline structure; if you look at graphite heat conduction values all of them come with values for conduction parallel or normall to the layers; diamond has no layered structure and heat conduction in diamond is isotropic; this is it is equal in all directions. Some anisotropic properties though may be introduced by the orientation and shape of grain interfaces and different materials on them (graphite is formed there); this asymmetry (when it exists) depends on the method used to make CVD diamond.
P1 Diamond Inc. in its engineering notes mentions CVD diamond heat conduction as isotropic and lists its heat spreaders as having 10W/cm/ºK in their conditions and terms; diamonex list heat conduction as 13W/cm/ºK; natural diamond has a somewhat higher heat conductivity.