Effect of hafnium carbide content on the ablative performance of carbon/carbon composites as rocket throats

Hafnium carbide (HfC) modified carbon/carbon (HfC-C/C) composites were prepared by impregnating carbon felts with a saturated HfOCl2 · 8H2O ethanol solution and heat treating at 600 °C to form HfO2/C composites that were then densified with pyrocarbon by chemical vapor infiltration and graphitized at 2100 °C to convert HfO2 into HfC. The HfC-C/C composites as rocket throats were ablated at 7 MPa and around 3200 °C for 3 s by an experimental solid rocket motor. Results showed that the HfC-C/C composites with HfC contents more than 5.7 wt.% had a stable period with a constant ablation rate and the duration of this period increased with HfC content. The overall ablation rate was decreased by 25.2% and 49.6% for the composites having 5.7 and 8.7 wt.% HfC respectively as compared with the composite with 2.5 wt.% HfC.