The ablation property of the carbon carbon composite material is the key factor of SRM.
The nozzle of the rocket or missile is under the situation of high speed air flow,and this kind of the material has the oxidization property,it will make the throat continuously in the ablation environment. The index of judging the material's erosion performance is mainly including: specific heat capacity,thermal conductivity,ablation rate,density etc. The good specific heat capacity can make the material absob much heat during the ablation process,and the low thermal conductivity can only make the high temperature gathered on the surface of the material,and can not transfer into the inside structure. The low density material can make the total weight lighter.
The ablation property of the material is related to many factors, first of all ,the different material has the different way to calculate the ablation rate. Secondly,except for the material ,the ablation rate is also related to the gas content and the tempterature of the environment,thirdly,the thermal conductivity of the gas flow also has an influence on the ablation property. In addition, the relationship between different factors is not isolated,they have the mutual influence. Nowadays,the ablation property of carbon cabon composite material is mainly thought as two parts,the thermal chemical ablation and the mechanical denuding.
Carbon carbon composite material still need to improve,and the main direction is below:
1、Increase the ablation property of the carbon carbon composite material. Some research show that make the C/C composite material impregnated with certain metal can reduce the ablation rate.
2、Optimization of process,the purpose of optimization of process is to “reduce the cost,improve the efficiency” .As is known to all,C/C composite material has many good properties,however,the technology is complex,and the production cycle is very long,and the cost of the processing is very high. So it limit the using on the SRM.
3、Strengthening mechanism research of the ablation process.