Ablation behavior of 3D-C_f/SiBCN composites with (PyC/SiC)₃ multi-layers as interphase was investigated in plasma ablation flame at a heat flux of 4.02 MW·m^-2. During ablation, amorphous SiBCN matrix is firstly oxidized and forms a borosilicate glass, in which B₂O₃ is volatilized as the ablation going on. At the ablation center with higher temperature, SiC and Si₃N₄ grains are precipitated from the amorphous SiBCN matrix. And then, these SiC and Si₃N₄ grains are oxidized, forming a certain viscous silica rich protective coating on the sample surface. Moreover, it is revealed that the SiC layers in (PyC/SiC)₃ multi-layers interphase can protect the carbon fibers from ablation damage effectively. Compared with the C_f/_(PyC)SiBCN composites, much improved ablation resistance is achieved for the C_f/_(PyC/SiC)3SiBCN composites. The linear and mass recession rates of the C_f/_(PyC/SiC)3SiBCN composites are as low as 1.7 ± 0.4 μm·s^-1 and 0.0427 ± 0.0053 mg·mm^-2s^-1, which are ∼43% and ∼21% lower than those of C_f/_(PyC)SiBCN.

以4.02 MW·m ^-2的热等离子烧蚀火焰研究了具有（PyC / SiC）₃多层作为相间相的3D-C _f / SiBCN复合材料的烧蚀行为。在烧蚀过程中，非晶态的SiBCN基体首先被氧化并形成硼硅酸盐玻璃，随着烧蚀的进行，其中的B ₂ O ₃挥发。在高温下的烧蚀中心，SiC和Si ₃ N ₄晶粒从非晶SiBCN基体中析出。然后，这些SiC和Si ₃ N ₄颗粒被氧化，在样品表面形成一定的粘性二氧化硅富集保护涂层。此外，揭示了（PyC / SiC）₃多层界面相中的SiC层可以有效地保护碳纤维免受烧蚀损害。与C _f / _（PyC） SiBCN复合材料相比，C _f / _{（PyC / SiC）3} SiBCN复合_材料的耐蚀性大大提高。C _f / _{（PyC / SiC）3} SiBCN复合_材料的线性和质量衰退率低至1.7±0.4μm·s ^-1和0.0427±0.0053 mg·mm ^-2 s ^-1，分别为〜43％和比C _f /低约21％_（PyC） SiBCN。