Preparation of self-healing Cf/SiBCN(O) composite using a novel polyborosilazane

In this study, novel polyborosilazane-derived SiBCN(O) ceramic was used as self-healing component in selfhealing C-f/SiBCN(O) composite, which was prepared by polymer infiltration and pyrolysis (PIP) process. Molecular-level structure design of boron-containing ceramic precursors was utilized to achieve uniform dispersion of boron-containing self-healing components in prepared composites. No elemental diffusion was observed at the interface of ceramic matrix and carbon fibers, which resulted in stable SiBCN(O) structure. In addition, boron was uniformly distributed in C-f/SiBCN(O) composite ceramic matrix, which was beneficial for self-healing of cracks. Cracks and indentations were able to heal at high temperatures in air. The best crackhealing behavior occurred in air atmosphere at 1000 degrees C, with nearly complete crack healing. This excellent self-healing behavior was achieved because silicon and boron atoms in SiBCN(O) ceramic reacted with available oxygen at high temperatures to form SiO2(l), B2O3(l), and B2O3 center dot xSiO(2) liquid phases, which effectively filled cracks. In general, as-prepared C-f/SiBCN(O) composite exhibited excellent self-healing properties and shows great application potential in high-temperature environment applications such as aviation, aerospace, and nuclear power.

Automated summary

The novel polyborosilazane-derived SiBCN(O) ceramic was effectively dispersed in the composite material, leading to excellent self-healing behavior. The reaction of silicon and boron atoms with oxygen at high temperatures effectively filled cracks, enhancing the self-healing properties of the composite.