The effect of zirconium carbide on ablation of carbon/carbon composites under an oxyacetylene flame

Ablation of zirconium carbide (ZrC) modified carbon/carbon (C/C) composites was tested by an oxyacetylene torch. The formation of zirconia from the oxidation of ZrC improves the ablation resistance of the C/C composites because of the evaporation at elevated temperature, which absorbs heat from the flame and reduces the erosive attack to carbon. Zirconia also acts as an accelerator for carbon oxidation as it reacts with carbon during the ablation, increasing the mechanical breakage rate of the fibres. However, the effect of mechanical breakage is inferior in the ablation of the composites. The heterogeneous reactions control the ablation of the composites.

Research highlights
► The ablation rates of C/C composites were decreased greatly after adding ZrC.
► Ablation mechanism of ZrC modified C/C composites was studied.
► ZrO2 played a double role including ablation resistance and accelerative oxidation.
► The evaporation of ZrO2 reduced the thermal erosive attack to carbon.
► The heterogeneous chemical reactions controlled the ablation of the composites.