Investigation of the thermal protection ablative properties of thermosetting composites with powder fillers: the corundum Al₂O₃ and the Carbon Powder C

Phenol formaldehyde resins were filled with mixtures of corundum Al₂O₃ and carbon C powders to produce thermoprotective composites. The composites were treated with hot combustion gases to determinate the temperature profiles across rectangular samples of dimensions 10x25x35 mm. The carbonization of the thermosetting matrix was observed. It was qualified the qualitative and the quantitative effect of components on the ablation surface temperature, the back side temperature of specimen and the mass waste under intensive heat fl ow after 120 s of treatment with hot combustion gases. The composites with higher matrix content (more liquid resin and less adhesive resin) and with predominance of corundum Al₂O₃ over carbon powder C showed the best insulating properties.