Microwave Absorption of Crystalline Fe/MnO@C Nanocapsules Embedded in Amorphous Carbon  

作　　者：Gaihua He Yuping Duan Huifang Pang 

机构地区：[1]Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province) , School of Materials Science and Engineering, Dalian University of Technology

出　　处：《Nano-Micro Letters》2020年第4期152-167,共16页纳微快报（英文版）

基　　金：Supported by Program for the National Natural Science Foundation of China (Nos. 51577021 and U1704253);the Fundamental Research Funds for the Central Universities (DUT17GF107)

摘　　要：Crystalline Fe/MnO@C core–shell nanocapsules inlaid in porous amorphous carbon matrix(FMCA)was synthesized successfully with a novel confinement strategy.The heterogeneous Fe/MnO nanocrystals are with approximate single-domain size which gives rise to natural resonance in 2–18 GHz.The addition of MnO2 confines degree of graphitization catalyzed by iron and contributes to the formation of amorphous carbon.The heterogeneous materials composed of crystalline–amorphous structures disperse evenly and its density is significantly reduced on account of porous properties.Meanwhile,adjustable dielectric loss is achieved by interrupting Fe core aggregation and stacking graphene conductive network.The dielectric loss synergistically with magnetic loss endows the FMCA enhanced absorption.The optimal reflection loss(RL)is up to−45 dB,and the effective bandwidth(RL<−10 dB)is 5.0 GHz with 2.0 mm thickness.The proposed confinement strategy not only lays the foundation for designing high-performance microwave absorber,but also offers a general duty synthesis method for heterogeneous crystalline–amorphous composites with tunable composition in other fields.Crystalline Fe/MnO@C core–shell nanocapsules inlaid in porous amorphous carbon matrix（FMCA） was synthesized successfully with a novel confinement strategy. The heterogeneous Fe/MnO nanocrystals are with approximate single-domain size which gives rise to natural resonance in 2–18 GHz. The addition of MnO2 confines degree of graphitization catalyzed by iron and contributes to the formation of amorphous carbon. The heterogeneous materials composed of crystalline–amorphous structures disperse evenly and its density is significantly reduced on account of porous properties. Meanwhile, adjustable dielectric loss is achieved by interrupting Fe core aggregation and stacking graphene conductive network. The dielectric loss synergistically with magnetic loss endows the FMCA enhanced absorption. The optimal reflection loss（RL） is up to-45 dB, and the e ective bandwidth（RL <-10 dB） is 5.0 GHz with 2.0 mm thickness. The proposed confinement strategy not only lays the foundation for designing high-performance microwave absorber, but also o ers a general duty synthesis method for heterogeneous crystalline–amorphous composites with tunable composition in other fields.

关 键 词：Crystalline nanocapsule Amorphous carbon Core–shell structure Interfacial polarization Microwave absorption 

分 类 号：TB34[一般工业技术—材料科学与工程]