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.