3D printing of (Cf-Csf)/ZrB2-SiC composites through coextrusion of flexible pre-infiltrated Cf/ZrB2 fiber bundle and Csf/ZrB2 paste

This work addresses two major challenges in 3D printed ceramic composites: inadequate ceramic matrix infiltration in fiber bundles and the lack of optimized fiber-matrix interfaces. We developed a breakthrough fabrication strategy featuring: A tailored flexible carbon coating specifically designed for 3D printing applications, deposited on carbon fibers to create a suitable interface; A specialized pre-infiltration method enabling uniform ceramic slurry distribution in continuous carbon fiber bundles; and A unique co-extrusion process combining flexible pre-infiltrated C f /ZrB 2 bundles with C sf /ZrB 2 paste. The resulting (C f -C sf )/ZrB 2 -SiC composites, fabricated through multi-cycle precursor infiltration-pyrolysis, demonstrate remarkable mechanical properties (flexural strength: 237.6 MPa; fracture toughness : 7.30 MPa m 1/2 ) and exceptional ablation resistance (enduring 2190 °C surface temperatures for 1320 s in wind tunnel testing). This work establishes a new paradigm for manufacturing ultra-high temperature ceramic composites with simultaneously enhanced mechanical and thermal performance.