Lightweight and multiscale ZrO2-SiOC coated carbon/phenolic composites with enhanced oxidation and ablation resistance

The carbon/phenolic composites are extensively considered as an efficient ablative thermal protection material, but inferior oxidation-ablation resistance has limited their further application. In this work, a multiscale ZrO2- SiOC coated carbon/phenolic composite (NCF/ZSAx-PA) was fabricated through a dual-stage construction strategy. The as-prepared composites exhibited a low density (0.314-0.348 g/cm3), low thermal conductivity (0.0605-0.0725 W/(m & sdot;k)) and promoted compressive strength (2.95/5.08 MPa in the Z/XY direction). Benefiting from the formation of a protective ZrO2-SiO2 ceramic coating, the multiscale composites showed excellent anti- oxidation and ablation performance. The residual weight of NCF/ZSAx-PA was 19.41 % at 1000 degrees C while the unmodified carbon/phenolic composites were entirely burnt off under an air atmosphere. Besides, the NCF/ ZSAx-PA exhibited low back temperature (53.6 degrees C), low linear ablation rate (0.0519 mm/s), and low mass loss rate (0.0100 g/s) under the 3.62 MW/m2 oxyacetylene assessment. All the superior properties enabled the NCF/ZSAx-PA a prospective application on the thermal protection system.