Mechanical properties and oxidative ablation behaviors of polysilazane-modified phenolic resin aerogel/carbon fiber fabric composites

Nanoporous composites have been extensively applied in aerospace applications for their outstanding thermal insulation and ablation resistance. A ceramizable polysilazane (PSZ)-modified phenolic resin (PSZ-PR)/carbon fiber fabric (PSZ-PR/CF) aerogel composite was synthesized through ambient pressure drying (APD). The homogeneous nanopore structure and improved thermal stability of the PSZ-PR aerogel matrix provided the composites with good performance (thermal conductivity as low as 0.126 W/(m & BULL;K)). The PSZ-PR/CF composites achieved high compressive strength (up to 43.75 MPa), tensile strength (59.22-124.75 MPa), and bending strength (23.35-97.94 MPa). Furthermore, the generation of ceramization products during the oxyacetylene flame ablation process, specifically SiC and Si3N4, enhanced the ablation resistance of PSZ-PR/CF composites: the linear ablation rates are as low as 0.112 and 0.018 mm/s at 4.18 MW/m2 (20 s) and 1.20 MW/m2 (120 s) of oxyacetylene heat flow, respectively. The corresponding maximum back temperatures are only 51.0 & DEG;C and 60.3 & DEG;C. Notably, the carbon/ceramic network is still present in the ablation layer to protect the carbon fibers from oxidation. This ceramizable PSZ-PR/CF composite has good potential for application in the field of thermal protection.HighlightsPSZ improves thermal stability and ablation properties of PSZ-PR/CF.The PSZ-PR/CF composites exhibit excellent mechanical and ablation properties.The ceramic products improve the scouring resistance of aerogel matrixes.The ceramizable PSZ-PR/CF was prepared by low-cost ambient pressure drying. The PSZ-PR/CF composites exhibited good mechanical properties and retained a good network structure after ablation test.image