Lightweight quartz fiber fabric reinforced phenolic aerogel with surface densified and graded structure for high temperature thermal protection

This paper reports a lightweight thermal protection composite with good anti-ablation and thermal insulation properties for service in high temperature environment. The needle quartz fiber (NQF) reinforced phenolic resin aerogel (PRA) composites with surface densification and graded structure were prepared using a mixture of ceramic resin (CR) as the surface layer and phenolic resin (PR) as the internal layer. The Tensile and bending strength of the dense layers were up to 39.22 MPa and 57.22 MPa, respectively. The complete volume rebounded compressive strength of the internal layer was 0.25 MPa and 2.94 MPa in Z and XY directions. In the ablation experiment, the backside temperature peaked at 52 °C within 3 min and 127 °C within 5 min whereas the surface temperature exceeded 1100 °C. Furthermore, the ablated surface remained flat and had a near ablation rate even at a temperature exceeding 1700 °C. The composites which combine insulation and anti-ablation exhibit a prospect in the fields of aerospace and retardant insulation.