Electromagnetic wave(EMW)absorbers with broadband attenuation and long-term stability are important for applications in marine environments.Dielectric ceramics excel in terms of thermal and chemical resistance but off...Electromagnetic wave(EMW)absorbers with broadband attenuation and long-term stability are important for applications in marine environments.Dielectric ceramics excel in terms of thermal and chemical resistance but offer limited impedance matching,whereas magnetic materials provide strong absorption but degrade rapidly due to corrosion.Herein,we present an engineering approach for polymer-derived ceramics that utilizes ferric crosslinking to integrate both magnetic functionality and hierarchical structure within a single system.By reacting iron(Ⅲ)acetylacetonate with Si–H groups in polyborosilazane,a uniformly distributed ferric polymer network is formed.Subsequent pyrolysis drives carbon nanotube growth and Fe_(x)Si_(y) phase formation,yielding a distinctive hierarchical“mushroom-like”structure composed of SiBCN matrices,carbon nanotube stems,and carbon-encapsulated Fe_(x)Si_(y) caps.This structure promotes EMW absorption via magnetodielectric synergy,rich interfaces,and multiple scattering,whereas carbon-encapsulated Fe_(x)Si_(y) in the SiBCN matrix provides corrosion resistance.The effective absorption bandwidth(EAB,defined as a reflection loss of less than-10 dB)of h-SiBCNFe reaches 8.16 GHz,while it also has a corrosion potential(E_(corr))of 0.033 V and an ultralow corrosion current(I_(corr))of 0.63μA·cm^(-2).These features highlight a new design strategy for developing advanced EMW absorbers tailored for marine applications.展开更多
基金support from the National Science Fund for Distinguished Young Scholars(Jie Kong)(No.52025034)the Joint Funds of the National Natural Science Foundation of China(Jie Kong)(No.U24A20204)+1 种基金the National Natural Science Foundation of China(Jin Liang,Zhen Yu)(Nos.52573096 and 52503112)the Innovation Team of Shaanxi Sanqin Scholars(Jie Kong).
文摘Electromagnetic wave(EMW)absorbers with broadband attenuation and long-term stability are important for applications in marine environments.Dielectric ceramics excel in terms of thermal and chemical resistance but offer limited impedance matching,whereas magnetic materials provide strong absorption but degrade rapidly due to corrosion.Herein,we present an engineering approach for polymer-derived ceramics that utilizes ferric crosslinking to integrate both magnetic functionality and hierarchical structure within a single system.By reacting iron(Ⅲ)acetylacetonate with Si–H groups in polyborosilazane,a uniformly distributed ferric polymer network is formed.Subsequent pyrolysis drives carbon nanotube growth and Fe_(x)Si_(y) phase formation,yielding a distinctive hierarchical“mushroom-like”structure composed of SiBCN matrices,carbon nanotube stems,and carbon-encapsulated Fe_(x)Si_(y) caps.This structure promotes EMW absorption via magnetodielectric synergy,rich interfaces,and multiple scattering,whereas carbon-encapsulated Fe_(x)Si_(y) in the SiBCN matrix provides corrosion resistance.The effective absorption bandwidth(EAB,defined as a reflection loss of less than-10 dB)of h-SiBCNFe reaches 8.16 GHz,while it also has a corrosion potential(E_(corr))of 0.033 V and an ultralow corrosion current(I_(corr))of 0.63μA·cm^(-2).These features highlight a new design strategy for developing advanced EMW absorbers tailored for marine applications.
