Properties of Isotropic Pyrolytic Carbon

As mentioned above, the structure of pyrolytic carbon is essentially isotropic and so are its properties. These are summarized in Table 7.3. 

Hardness. Being composed of minute crystallites with essentially random orientation, isotropic pyrolytic carbon lacks the easy interlayer slippage which is characteristic of the well-oriented laminar or columnar structures of pyrolytic graphite. As a result, it is considerably harder. This makes it easy to polish and the material can be given a high gloss. The wear resistance is usually superior to that of the columnar and laminar deposits of vitreous carbon. PS) 

Mechanical Properties. Isotropic pyrolytic carbon is stronger than the oriented pyrolytic graphites and vitreous carbon and can be considered as a reasonable structural material, comparing favorably with some of the more brittle ceramic materials. 

Flexural strength, MPa Young s modulus, GPa Strain to failure, % 

Gas Permeability. Isotropic pyrolytic carbon provides a better barrier to gases than the more crystalline pyrolytic graphites.l l The permeability, K, is as follows  

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Table 7.3. Properties of Isotropic Pyrolytic Carbon at 25°C (as deposited)...

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