In this work, three-dimensional (3D) C_f/SiBCN composites were fabricated by polymer infiltration and pyrolysis (PIP) with poly(methylvinyl)borosilazane as SiBCN precursor. The 3D microstructure evolution process of the composites was investigated by an advanced X-ray computed tomography (XCT). The effect of dicumyl peroxide (DCP) initiator addition on the crosslinking process, microstructure evolution, and mechanical properties of the composites were uncovered. With the addition of a DCP initiator, the liquid precursor can cross-linking to solid-state at 120 °C. Moreover, DCP addition decreases the release of small molecule gas during pyrolysis, leading to an improved ceramic yield 4.67 times higher than that without DCP addition. After 7 PIP cycles, density and open porosity of the final C_f/SiBCN composite with DCP addition are 1.73 g·cm⁻³ and ∼10%, respectively, which are 143.0% higher and 30.3% lower compared with the composites without DCP addition. As a result, the flexural strength and elastic modulus of C_f/SiBCN composites with DCP addition (371 MPa and 31 GPa) are 1.74 and 1.60 times higher than that without DCP addition (213 MPa and 19.4 GPa), respectively.

在这项工作中，通过以聚（甲基乙烯基）硼硅氮烷为SiBCN前体的聚合物渗透和热解（PIP）来制造三维（3D）C _f / SiBCN复合材料。通过先进的X射线计算机断层扫描（XCT）研究了复合材料的3D微结构演化过程。发现过氧化二枯基（DCP）引发剂的添加对交联过程，微观结构演变和复合材料力学性能的影响。通过添加DCP引发剂，液态前体可以在120°C交联成固态。此外，添加DCP减少了热解过程中小分子气体的释放，从而导致陶瓷产率比未添加DCP的提高了4.67倍。经过7个PIP循环后，最终C _f的密度和开孔率添加DCP的/ SiBCN复合材料分别为1.73 g·cm ^-3和〜10％，与未添加DCP的复合材料相比，分别高143.0％和30.3％。结果，添加DCP（371 MPa和31 GPa）的C _f / SiBCN复合材料的弯曲强度和弹性模量分别比不添加DCP（213 MPa和19.4 GPa）的弯曲强度和弹性模量高1.74倍和1.60倍。