Carbon carbon composite material has the similar properties as the graphite material,such as low density,high-thermal resistance,ablation resistance,high strength,good thermal shock resistance and easy designed etc. meanwhile it also has some other properties which graphite material doesn’t have,such as brittleness of polycrystalline graphite,and the easy layering property of the pyrolytic graphite. Now the carbon carbon composite material is the most appropriate material used for the throat,nozzle of the rocket engine.
The carbon carbon composite material consists of two parts: carbon fiber perform and the carbon matrix. The structure of material decides the property of it. To the C/C composite material,as for the anisotropy,the structure and the performance of the material is very complex.
The property of carbon carbon composite material is decided from the property of carbon fiber,carbon matrix,and the interfacial properties of the fiber and carbon matrix. The carbon fiber is the base of the carbon carbon composite perform. The thermal property,strength property and the physical property can be designed and controled according to the different structure parameter,the parameters mainly include:the direction of the carbon fiber,the content of the carbon fiber,the space of the arrangement,the density of the carbon matrix,the type of the carbon fiber etc. With the dimension of carbon fiber structure increasing,the anisotropic of C/C material will decrease,and the strength of the material will increase,and the ablation performance of different direction will be more and more symmetry. However,with the dimension of the fiber increasing,the cost of the perform will be much more expensive,and it will be harder to densify.
The multi dimensional braided or acupuncture is to improve the Z axis or other non X-Y axis strength and thermal property of the carbon perform. But the cost of multi dimensional is too much ,and the hole in the embryo is bigger,it’s not easy to use CVI to meet a higher density. This kind of the perform is mostly used for the throat of the missile and rocket engine.