Carbon foam reinforced SiBCN ceramic aerogel with multifunctional performances

Abstract 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.