Pyrolytic carbon

Pyrolytic carbon is a material similar to graphite, but with some covalent bonding between its graphene sheets as a result of imperfections in its production.

It is used in high temperature applications such as missile nose cones, rocket motors, heat shields, laboratory furnaces, in graphite-reinforced plastic, coating nuclear fuel particles, and in biomedical prostheses.

With the easy availability of rare-earth permanent magnets developed in the 1970s and 1980s, the strong diamagnetism of pyrolytic graphite makes it a convenient demonstration material for this effect.

In 2012, a research group in Japan demonstrated that pyrolytic graphite can respond to laser light or sufficiently powerful natural sunlight by spinning or moving in the direction of the field gradient.

When sunlight hits these pyrolytic carbon-coated grains they lose electrons due to the photoelectric effect and become paramagnetic and are pulled back to the main ring structure as they are now attracted to Saturn's equatorial magnetic field.

Because blood clots do not easily form on it, it is often advisable to line a blood-contacting prosthesis with this material in order to reduce the risk of thrombosis.

Blood vessel stents, by contrast, are often lined with a polymer that has heparin as a pendant group, relying on drug action to prevent clotting.