Modification of SiBCN by Zr atom and its effect on ablative resistance of Cf/SiBCN(Zr) composites

The SiBCN(Zr) ceramics were synthesized via a polymer-derived ceramics route. Using this precursor, the precursor impregnation pyrolysis process prepared the Cf/SiBCNZr composites with low density (1.89 g/cm3). Compared to Cf/SiBCN, the Cf/SiBCNZr composites exhibit reliable thermal stability and ablation resistance in a wide temperature range. A dense oxide layer dominated by ZrO2 and SiO2 formed in situ on the surface of Cf/SiBCNZr, effectively preventing outside oxygen and further ablation. The introduced Zr is evenly distributed in SiBCN ceramics, which enables it to give full play to the ablation resistance of Zr at higher oxygen acetylene torch temperatures. This work enriches the fundamental understanding and offers engineering guidance for lightweight ultra-high temperature ceramic matrix composites.