Erosion of carbon/carbon composites using a low-velocity, high-particle-concentration two-phase jet in a solid rocket motor

The erosion of a four-direction carbon/carbon composite test piece using a low-velocity, high-particle-concentration two-phase jet was studied by the hot firing test of a small solid rocket motor with an elaborately designed flow path. The linear ablation rates were measured. The ablation surface and microstructure of the carbon/carbon composites were studied by scanning electron microscopy, and the ablation mechanism was investigated. Within the parameter range studied in this paper, mechanical erosion is found to play a dominant role in the ablation of carbon/carbon composites in the impact region. Moreover, the effect of chemical ablation is weak. The erosion of carbon/carbon composites results in blunt fracture tip fibers and a lamellar matrix. The particle impact mass flux is more dominant than the particle impact velocity in the erosion of carbon/carbon composites. At mesoscale, the carbon rods are more resistant to mechanical erosion than fiber bundles. At microscale, the carbon fibers are more susceptible to mechanical erosion than the carbon matrix, whereas the carbon fibers are more resistant to chemical ablation than the matrix and interface.