Electromagnetic wave-absorbing(EMA)materials at high temperatures are limited by poor conduction loss(L_(c)).However,adding conductors simultaneously increases the conduction loss and interfacial polarization loss,lea...Electromagnetic wave-absorbing(EMA)materials at high temperatures are limited by poor conduction loss(L_(c)).However,adding conductors simultaneously increases the conduction loss and interfacial polarization loss,leading to a conflict between impedance matching(Z_(in)/Z_(0))and electromagnetic wave loss.This will prevent electromagnetic waves from entering the EMA materials,finally reducing overall absorbing performance.Here,the effective electrical conductivity(σ)is enhanced by synchronizing particle size and grain number of Ti_(3)AlC_(2) to increase the conduction loss and avoid the conflict between the impedance matching and the electromagnetic wave loss.As a result,the best-absorbing performance with an effective absorption bandwidth(EAB)of 4.8 GHz(10.6–15.4 GHz)at a thickness of only 1.5 mm is realized,which is the best combination of wide absorption bandwidth and small thickness,and the minimum reflection loss(RL_(min))reaches−45.6 dB at 4.1 GHz.In short,this work explores the regulating mechanism of the EMA materials of effective electrical conductivity by simulated calculations using the Vienna ab-initio Simulation Package(VASP)and COMSOL as well as a series of experiments,which provide new insight into a rational design of materials with anisotropic electrical conductivity.展开更多
The high-speed advances in electromagnetic(EM)wave and laser detection technology have accelerated the innovation of absorbing materials toward specific multi-band compatibility.It is difficult to achieve dual absorpt...The high-speed advances in electromagnetic(EM)wave and laser detection technology have accelerated the innovation of absorbing materials toward specific multi-band compatibility.It is difficult to achieve dual absorption of EM waves and near-infrared lasers by absorbing materials in a single frequency band;the design of high-performance laser-EM wave multi-band compatible absorbing materials is imminent.Herein,ErBO_(3)@ATO(erbium borate/antimony-doped tin oxide)porous composite microspheres with an average size of 15-20μm are produced solvothermal method and self-assembly,which exhibit excellent laser-EM wave compatible absorption.The porous structure on the surface of ErBO_(3)microspheres provides heterogeneous nucleation sites for ATO particle deposition.The minimum reflectivity of the composite for1.06 and 1.54μm lasers is 9.59%and 4.79%,which is0.57%and 3.78%lower than those of pure ATO particles,respectively.The composites containing 70 wt%porous ErBO_(3)@ATO reveal the minimum reflection loss(RL)value of-31.6 dB,and an effective absorption band width reaches 2.08 GHz at 2.5 mm thickness.The mechanism of near-infrared laser and EM wave compatible absorption is the synergistic effect of the energy level transition of ErBO_(3)and the dielectric loss of ATO,coupled with the large surface area and porous structure of the micro spheres.Therefore,the designed porous ErBO_(3)@ATO composite microspheres can be an attractive choice for lasers and EM wave high-quality compatible absorption.展开更多
文摘Electromagnetic wave-absorbing(EMA)materials at high temperatures are limited by poor conduction loss(L_(c)).However,adding conductors simultaneously increases the conduction loss and interfacial polarization loss,leading to a conflict between impedance matching(Z_(in)/Z_(0))and electromagnetic wave loss.This will prevent electromagnetic waves from entering the EMA materials,finally reducing overall absorbing performance.Here,the effective electrical conductivity(σ)is enhanced by synchronizing particle size and grain number of Ti_(3)AlC_(2) to increase the conduction loss and avoid the conflict between the impedance matching and the electromagnetic wave loss.As a result,the best-absorbing performance with an effective absorption bandwidth(EAB)of 4.8 GHz(10.6–15.4 GHz)at a thickness of only 1.5 mm is realized,which is the best combination of wide absorption bandwidth and small thickness,and the minimum reflection loss(RL_(min))reaches−45.6 dB at 4.1 GHz.In short,this work explores the regulating mechanism of the EMA materials of effective electrical conductivity by simulated calculations using the Vienna ab-initio Simulation Package(VASP)and COMSOL as well as a series of experiments,which provide new insight into a rational design of materials with anisotropic electrical conductivity.
基金financially supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)"Qinglan Project"Young and Middle-aged Academic Leaders Program of Jiangsu Province。
文摘The high-speed advances in electromagnetic(EM)wave and laser detection technology have accelerated the innovation of absorbing materials toward specific multi-band compatibility.It is difficult to achieve dual absorption of EM waves and near-infrared lasers by absorbing materials in a single frequency band;the design of high-performance laser-EM wave multi-band compatible absorbing materials is imminent.Herein,ErBO_(3)@ATO(erbium borate/antimony-doped tin oxide)porous composite microspheres with an average size of 15-20μm are produced solvothermal method and self-assembly,which exhibit excellent laser-EM wave compatible absorption.The porous structure on the surface of ErBO_(3)microspheres provides heterogeneous nucleation sites for ATO particle deposition.The minimum reflectivity of the composite for1.06 and 1.54μm lasers is 9.59%and 4.79%,which is0.57%and 3.78%lower than those of pure ATO particles,respectively.The composites containing 70 wt%porous ErBO_(3)@ATO reveal the minimum reflection loss(RL)value of-31.6 dB,and an effective absorption band width reaches 2.08 GHz at 2.5 mm thickness.The mechanism of near-infrared laser and EM wave compatible absorption is the synergistic effect of the energy level transition of ErBO_(3)and the dielectric loss of ATO,coupled with the large surface area and porous structure of the micro spheres.Therefore,the designed porous ErBO_(3)@ATO composite microspheres can be an attractive choice for lasers and EM wave high-quality compatible absorption.
