Graphite-Pyrolytic Grade
Description:
Pyrolytic graphite is a unique form of graphite manufactured by decomposition of a hydrocarbon gas at very high temperature in a vacuum furnace. The result is an ultra-pure product which is near theoretical density and extremely anisotropic. This anisotropy results from the layered structure. As an example, pyrolytic graphite exhibits thermal conductivity consistent with the best conductors in the 'a-b' plane and lower than alumina brick in the 'c' direction. Mechanical, thermal, and electrical properties are generally far superior to conventional graphites. Some other features of pyrolytic graphite include:
- Chemically Inert
- High Purity
- Stable to 3000 oC
- Impermeable
- Directional Electrical & Thermal Characteristics
- Self-Lubricating
- Nondusting
- Low Etch Rate
Typical Physical Properties (Room Temperature):
Density: 2.18 - 2.22 g/cc
Flexural Strength (a-b): 18,000 psi (120 MPa)
Tensile Strength (a-b): 12,000 psi (80 MPa)
Compressive Strength (a-b): 15,000 psi (100 MPa)
Young’s Modulus (a-b): 3 x 106 psi (20,000 MPa)
Crystal Structure: Hexagonal
(C/2 Spacing): (3.42 Å)
Melting Point (Atmosphere): Sublimes at 3650 oC
Outgassing: Negligible
Coefficient:
Thermal Expansion (a-b): 0.5 x 10-6 cm/cm/oC
Thermal Expansion(c): 6.5 x 10-6 cm/cm/oC
Thermal Conductivity (a-b): 400 Watts/Meter oC
Thermal Conductivity (c): 3.5 Watts/Meter oC
Electrical Resistance (a-b): 0.5 10-3 ohm-cm
Electrical Resistance (c): 0.5 ohm-cm
Purity:
Total Impurities: .01% Maximum
Total Metallic: 10 ppm
