Carbon foam reinforced SiBCN ceramic aerogel with multifunctional performances

Silicon boron carbonitride (SiBCN) ceramic aerogels have gained great interests for their excellent high-temperature stability, thermal insulation, and low density, capable of achieving multifunctional applications. Here, a carbon foam reinforced SiBCN aerogel (CF/SiBCN) was prepared using polyborosilazane (PBSZ) as precursor and melamine-derived carbon foam (CF) as skeleton via hydrothermal assembly, freeze‒drying, and pyrolysis. The CF/SiBCN aerogel exhibits a low density (0.13‒0.58 g cm −3 ) and high porosity (68.1%‒91.9%) by adjusting PBSZ content in cyclohexane solution. Benefiting from their highly porous structure, the CF/SiBCN aerogels realize a low thermal conductivity of 0.04‒0.05 W m −1 K −1 and good structural stability after thermal treatment in Ar, showing potential application in thermal insulation field under high-temperature environments. Moreover, the 1400°C-carbonized CF as conductive network significantly enhances the electrical conductivity of the CF/SiBCN aerogel up to 320 S m −1 , thus attaining a high electromagnetic interference SE Total value of 33.7 dB as well as notable Joule heating (95.6°C at 4.0 V) performance. Consequently, it is an effective approach to develop novel SiBCN aerogel composites to expanding their usage in structural and multifunctional fields.