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

Abstract

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, ZrSi2 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 ZrSi2. The thermal conductivities of the composites with different ZrSi2 contents ranged from 0.219~0.254 W/K·m. A continuous but not very compact cover was formed on the ablating surface of the C-Ph composite with 10% ZrSi2, 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% ZrSi2 exhibited the lowest linear loss rate (0.0081 mm/s) and the best heat insulating performance.