Boron and Nitrogen Doping in Fused Silica Ceramics: Structural, High-Temperature Mechanical and Long-Term Ablation Resistance Properties of Si-B-O-N Ceramics

SiBON ceramics, which are multielement composite systems, are developed by incorporating boron and nitrogen into fused silica ceramics, which enhances the anti-crystallization, mechanical, and ablation properties of these materials. Integrating boron and nitrogen hybridizes the glass lattice structure, significantly improving the anti-crystallization capability of the system. At room temperature, the flexural strength of a SiBON ceramic reaches 104 MPa, which is a significant improvement over that of pure fused silica ceramics. Notably, the flexural strengths at 900 °C and 1000 °C are 190 MPa and 153 MPa, respectively, surpassing the value at room temperature, with permanent plastic deformation occurring above 1100 °C. The ceramics are tested under a plasma flame for 300 s at heat flux densities of 5.18 MW/m² and 8.30 MW/m², yielding line ablation rates of -1.24 μm/s and 5.06 μm/s and mass ablation rates of -0.03 mg/s and 1.06 mg/s, respectively. The amorphous oxide layer serves as the primary ablation-resistant barrier.