Ablation performance and mechanism of fibrous monolithic ZrB₂-SiC ceramics prepared by wet-spinning co-extrusion method under plasma flame

The fibrous monolithic structure exhibits extensive graded fracture as well as load redistribution upon fracture due to the unique layered microstructure, providing an effective way to toughen ceramic materials. In this work, fibrous monolithic ZrB2-SiC/SiCw (FZS(w)) and fibrous monolithic ZrB2-SiC/BN ceramics (FZB) were prepared by wet-spinning and co-extrusion method using SiCw and BN as the interfacial layer. The strengths, toughness, and the work of rupture of FZS(w) were 117 MPa, 3.9 MPa m(1/2), 104 J/m(2), while that of FZB were 103 MPa, 2.6 MPa m(1/2), 98 J/m(2), respectively. FZS(w) and FZB were subjected to 200 s plasma ablation tests under 12.84 MW/m(2) and plasma flame above 3000 degrees C. The mass and linear ablation rates of FZS(w) after testing were -0.34 mg/s and -0.2 mu m/s, respectively, and remain intact, showing non-ablation characteristics, while FZB underwent delamination and destruction. The introduction of SiCw interface layer improved the thermal conductivity of FZS(w) and reduced the surface temperature of FZS(w). Higher oxidation temperature and higher SiC content of the SiCw interface layer result in a great quantity of SiO2, which effectively isolated oxygen from further erosion.