Improved ablation resistance of C–C composites using zirconium diboride and boron carbide

Zirconium diboride and boron carbide particles were used to improve the ablation resistance of carbon–carbon (C–C) composites at high temperature (1500 °C). Our approach combines using a precursor to ZrB2 and processing them with B4C particles as filler material within the C–C composite. An oxyacetylene torch test facility was used to determine ablation rates for carbon black, B4C, and ZrB2–B4C filled C–C composites from 800 to 1500 °C. Ablation rates decreased by 30% when C–C composites were filled with a combination of ZrB2–B4C particles over carbon black and B4C filled C–C composites. We also investigated using a sol–gel precursor method as an alternative processing route to incorporate ZrB2 particles within C–C composites. We successfully converted ZrB2 particles within C–C composites at relatively low temperatures (1200 °C). Our ablation results suggest that a combination of ZrB2–B4C particles is effective in inhibiting the oxidation of C–C composites at temperatures greater than 1500 °C.