The status and role of carbon-carbon composites in medical applications
Carbon has the best biocompatibility of all materials, and carbon-carbon composites inherit this property, which makes them the best materials for surgical implants used under high stress.2D Carbon carbon was used successfully in the 1980s for artificial joints and as dental root implants. Carbon-carbon composites have the following characteristics as bone replacement and bone repair materials:
1 Stable in vivo and omit good safety
Compared with metal implants, carbon-carbon composites have better in vivo stability and biosafety. Carbon-carbon composites are biologically inert materials, not easy to react with human tissues, can withstand changes in the acid and alkaline environment in the body, and are not easy to deform. However, the particles of metal implants are easily dislodged, and then deposited in some organs of the human body, which are phagocytosed by cells and may cause matrix poisoning or other adverse reactions.
2 Good biocompatibility
Relative to other biomaterials, carbon-carbon composites are composed of carbon, which also determines its excellent biocompatibility, which is also confirmed by current basic and clinical research.
3 Modulus of elasticity is similar to bone and has high strength and toughness.
The modulus of elasticity of carbon-carbon composites is 45-47GPa, which is similar to the modulus of elasticity of human bones (10-40GPa), and it has very good stress transfer ability, which can avoid the occurrence of “stress shielding” effect. In addition, the strength of carbon-carbon composites is also very high, it can also meet the requirements of the strength of human hard tissue replacements, is a potential advantage of the human bone replacement material. With further research and technological advances, the successful development of personalized carbon-carbon composite implants is also feasible.
4 Osteoblasts grow in well
Some studies have shown that osteoblasts can grow into the surface of carbon-carbon composites, which is more advantageous compared to metallic materials. It binds better to the human skeleton, enhances firmness, and can integrate better with the muscle. The reason is related to the characteristics of the carbon-carbon composite material itself, based on the carbon material is one of the components of the human body, and the carbon-carbon composite material surface and internal is microporous, which is conducive to the bone growth into the bone, and has an inducing effect on the bone growth into the bone. The internal pore size of the material can be adjusted appropriately through the process technology, which makes the degree of bone ingrowth different. Similarly, the dimension of the material and the roughness of the surface can be adjusted to stimulate osteoblasts and induce osteoclasts to grow into the material better, and in the future, if the material can be molded to form a trabecular structure, it can be better for osteoclasts to grow into.
The status and role of carbon-carbon composites in the application of solar energy field
Carbon-carbon composites used in solar photovoltaic hot field material components mainly include: polysilicon hydrogenation furnace with internal and external heat preservation barrels, U-type heating and heat preservation plate; polysilicon ingot casting furnace with a cover plate, crucible guard, crucible bottom bracket, heat preservation plate; direct-drawing monocrystalline silicon furnaces with a monolithic crucible, deflector, heater, cover plate, bottom bracket, internal and external heat preservation barrels; silicon wafers PECVD coating with pallets guide rail strips.
In the field of solar energy, straight pull silicon monocrystalline furnace and polysilicon ingot casting furnace are the main equipment for the production of silicon wafers, and their core components are all high-purity graphite materials. With the development of the solar photovoltaic industry, the traditional graphite material is difficult to meet the large-scale demand for direct-drawing monocrystalline silicon and polycrystalline silicon ingot casting furnace production equipment, but carbon-carbon composite materials have good thermo-physical properties, and compared with the graphite field materials, has a very big advantage. Carbon and carbon composites insulation parts, structural parts and heat generator is the direction of development of the thermal field material of direct-draw monocrystalline silicon furnace, polysilicon ingot casting furnace and other photovoltaic equipment. Carbon-carbon composite heat field has more advantageous performance compared with graphite material heat field. Its life span is more than 3 times of graphite material, while the price is only about 2 times of graphite crucible. Therefore, carbon-carbon composites have been used as a good substitute for graphite materials in direct-draw monocrystalline silicon furnaces and polysilicon ingot casting furnaces.
The status and role of carbon-carbon composites in nuclear energy applications
The thermal conductivity of carbon-carbon composites is affected by the alignment direction of the carbon fibers, the type of matrix carbon, and the heat treatment temperature. For example, the thermal conductivity of bidirectionally aligned carbon fibers at room temperature is usually 5-150W/(m.K), the thermal conductivity of the largest [500W/(m.K)] of the carbon-carbon composites are specially developed for nuclear fusion plants, using ultra-high processing temperature can form a few numbers of graphite-like substrate structure. Utilizing the high-strength, low-density, and dimensionally stable characteristics of carbon-carbon composites, they can be used in nuclear reactors to make wireless point frequency limiters, plasma materials for nuclear fusion reactors, and heat dissipation fins.