- Thermoelectric Materials

 

Pyrolytic Graphite Substrate

Pyrolytic Graphite is a unique form of graphite manufactured by decomposition of a hydrocarbon gas at very high temperature in a vacuum furnace.    It is nucleated on substrate and grown with texture along C axis.    The result is an ultra-pure product which is near theoretical density and extremely anisotropic.    The material is grown onto a substrate giving it a layered composition.    This also means it has different properties in different planes.    In the C plane (across its layers) it has low thermal conductivity, acting as an insulator.    In the A-B plane (with the layers) it has very high thermal conductivity, acting as a superb conductor.    All values are taken at room temperature, unless noted otherwise.
 
■   Typical Properties
PROPERTY US VALUE METRIC VALUE
Density 0.079 lb/in 3 2.2 gr/cm 3
Flexural Strength - AB 13000 psi 89.6 mpa
Compressive Strength - AB 15000 psi 103.4 mpa
Compressive Strength - C 25000 psi 172.4 mpa
Shear Strength - AB 1000 psi 6.9 mpa
CTE - AB 0.8 in/in °F x 10 -6 0.5 Microns/m °C
CTE - C 11 in/in °F x 10 -6 6.5 Microns/m °C
Thermal Conductivity - AB 232 BTU/(h.ft 2 °F/ft) 400 W/(m 2 . K/m)
Thermal Conductivity - C 2 BTU/(h.ft 2 °F/ft) 3.5 W/(m 2 . K/m)
Resistivity (RT) - AB 0.2 * 10-3 ohm/inch 0.5 * 10-3 ohm/cm
Resistivity (1650C) - AB 0.1 * 10-3 ohm/inch 0.3 * 10-3 ohm/cm
Resistivity (RT) - C 0.2 ohm/inch 0.5 ohm/cm
Resistivity (1650C) - C 0.1 ohm/inch 0.3 ohm/cm
Oxidizing Atmosphere 1200 °F 649 °C