Silver particle-modified BN@C composites for thermal management and microwave absorption

Composite materials with good thermal conductivity and wave-absorbing ability are an important innovation in the multifunctionalization of current wave-absorbing materials. However, how to make wave-absorbing materials with high thermal conductivity, is still a difficult problem to overcome in the field of electromagnetic wave absorption (EWA). In this paper, boron nitride nanosheets were modified by surface polymerization of phenolic aldehyde, and the impedance matching properties of the materials were optimized by trace silver modification, after which they were annealed at 700 °C and blended with silicone rubber. The results made clear, that it achieves excellent absorption bandwidth (6.89 GHz) at a lower thickness (2.3 mm), while the thermal conductivity of the composite reaches 0.42 W/(m•k) at this performance of the filler ratio, which is a 210% enhancement compared to the thermal conductivity of pure silicone rubber [0.2 W/(m•k)], and is only 0.02 W/(m•k) lower than pure BN composites at the same filling ratio. This shows that the prepared material not only has good microwave absorption ability, but also has excellent thermal conductivity. The material is simple to make. It has a high industrialization potential and can serve as a powerful guide for the development of ceramic materials into heat-conducting and wave-absorbing materials in the future.