One way to decrease the ablation property of the carbon carbon composite material is add the coating which can be antioxidant and anti-scouring during the high temperature. Now the recognized method in the international community is HfC,TaC,ZrC and SiC etc. The technology mainly include CVI/CVD,CVR, liquid phase impregnation and coating. The C/C composite material throat made in Russia,using the Hf and Ta to dip into it,which can bear the 3800 centigrade and meet 8.0Mpa pressure,the ablation property is much lower than the normal carbon carbon composite throat.
The SiC coating C/C composite material can be made from two different kinds of the composite material matrix,one is needle felt reinforced material,using the CVD to densify to 1.3g/cm3 then using resin impregnant to meet density 1.8g/cm3 or even more than that,another way is puncturing reinforced matrix,the Si element is purity >99.3% and 300mesh Si powder,under the 1600centigrade high tempterature furnace,the Si steam has a chemical reaction with the C elecment,and meet the SiC coating on the surface of the C/C material.
During the ablation processing,the SiC coating reduce the ablation rate of carbon carbon composite material,and improve the ablation property,the SiC can have a protect fuction instantaneous.
Different working environment,the C/C composite material show different ablation morphologies,and meanwhile,it has the different ablation mechanism,generally speaking,the carbon carbon composite material used for SRM mainly affected by two aspects,one is thermal-chemical ablation and another one is mechanical denuding,the scouring of the grain can increase the changing of the thermal conductivity and strength and other strength,even break the structure of the material.when the different parts of the throat has the different ablation,then it will lead to the different ablation result.
