Development of high performance nano filled Ceramic coated carbon fiber reinforced composites

Abstract

Thermal protection materials are required to safeguard the hypersonic or re-entry vehicle from intense heating conditions. At the time of re-entry flight, various parts of the vehicle are subjected to harsh thermal and mechanical loads. Thus, the material of the re-entry vehicle parts must withstand the stresses and heat flux generated by these loads under harsh conditions. Carbon-phenolic (C-Ph) composites exhibits excellent mechanical and thermal properties. During the ablation process, the phenolic resin oxidizes into char residues and a char layer forms on the ablative surface that reduce the ablation rate by reradiating the heat energy to the gas phase. However, the C-Ph composites are unable to endure the ablation and rapid oxidation when subjected to extreme high-temperature and high-velocity conditions. newlineIn this study, several experiments were performed to investigate the mechanical, ablation and thermal properties of C-Ph composites. The ZrO2, ZrO2/CNTs, ZrO2/GNPs and ZrO2/SiC hybrid fillers were synthesized using sol-gel technique followed by individual incorporation into C-Ph composites. In order to compare the mechanical, thermal and ablation performance of filler reinforced composites, the blank C-Ph composite formulation was also fabricated. The thermal stability of these C-Ph composites was analyzed using thermogravimetry analysis (TGA) newline newlineand derivative thermogravimetric analysis (DTG). To study the effect of various additive fillers on the thermal stability of the composites, the decomposition temperatures were evaluated and compared with the controlled sample. It was observed that the addition of ZrO2 filler to C-Ph composite enhanced the thermal stability that can be attributed to decreased the chain mobility of the phenolic matrix. newlineThe addition of CNTs hybrid fillers further improved the thermal decomposition temperatures and thermal stability of the composites compared to that of the pure C-Ph composite. With GNPs based composites, the improved thermal stability of was due to the char residue