Biomedical applications: Biomedical applications require a material with good strenth, fatigue-resistance, high erosion resistance, chemical inertness, and compatibility with blood and tissues. Isotropic pyrolytic carbon meets these criteria and is used extensively in biomedical devices such as heart valves and dental implants where its performance is superior to other forms of carbon such as pyrolytic graphite or vitreous carbon.
Coatings for molded graphite: A pyrolytic graphite coating, applied to a molded graphite substrate, provides a smooth, essentially pore-free surface that can enhance the chemical resistance. Such coated parts are found in applications requiring chemical inertness at high temperature such as the following:
– Wafer trays for plasma-CVD equipment.
– Boats for liquid-phase epitaxy.
– Boats, and other parts for vapor deposition for Ⅲ-Ⅴ semiconductor compounds such as gallium arsenide.
– Hardware for metal processing.
Coating for fibers: Inorganic fibers, such as silicon carbide or alumina, provide the reinforcement for metal or ceramic matrices to form refractory composites. These fibers often react with the matrix material during processing into composites or during operation at high temperature. This interaction produces intermetallics or other compounds which may considerably degrade the properties of the composite. A pyrolytic graphite coating applied on the fiber acts as a diffusion barrier, and prevents these diffusional reactions.
Another fiber coating application is found in fiber optics. An isotropic pyrolytic-carbon coating is applied on optical fibrs to improve the abrasion and fatigue resistance, and bending performance.
Carbon-carbon infiltration: Pyrolytic carbon or graphite is used to densify carbon-carbon structures by infiltration as described in other articles. Applications include reentry heat shields, rocket nozzles, aircraft disk brakes, and other aerospace components.