The effects of ZrSi₂ on the ablation and insulation performances of low-density carbon-phenolic composites

Carbon-phenolic (C-Ph) composites are typical ablative thermal protection materials. Excellent ablation and insulation performance indicate a decreased thickness of the thermal shield. Thus, ZrSi 2 particles were introduced to improve the performance of the low-density C-Ph composite. An oxyacetylene flame torch was used to examine the ablation and insulating characteristics. The curing process of the matrix resin was not affected by ZrSi 2 . The thermal conductivities of the composites with different ZrSi 2 contents ranged from 0.219 ∼ 0.254 W K −1 ·m −1 . A continuous but not very compact cover was formed on the ablating surface of the C-Ph composite with 10% ZrSi 2 , which limited the escape of the charred matrix. The passageways for the gaseous products of the charring phenolic compounds were also not impeded by this cover. The C-Ph composite with 10% ZrSi 2 exhibited the lowest linear loss rate (0.0081 mm s −1 ) and the best heat insulating performance.