High temperature self-healing SiBCN ceramics derived from hyperbranched polyborosilazanes

Self-healing functionality is an important issue of ceramics or ceramic matrix composites used in high temperature and oxidation environment. In this contribution, we reported the cross significant crack self-healing behaviors and mechanism of SiBCN ceramics derived from hyperbranched polyborosilazanes. The self-healing ability of cracks and indention cross sign are enhanced with the increase of oxidation time. And the temperature also influences the healing self-behaviors. The crack healing and indention sign occurred at 1000 °C in air atmosphere. The ceramics with high content of boron show much more obvious self-healing performance because the silicon and boron atoms can be reacted with the available oxygen at high temperature to form SiO₂(l), B₂O₃(l), and B₂O₃.SiO₂. The liquid-like products will fill the crack and prevents the destructive of substrates. The preceramic precursor-derived SiBCN ceramics show good self-healing performance and possess great potential in aeronautics, aerospace, and nuclear power industries. [Figure not available: see fulltext.]