Graphene nanosheet- and flake carbonyl iron particle-filled epoxy–silicone composites as thin–thickness and wide-bandwidth microwave absorber

Multi-walled carbon nanotube (MWCNTs)-and CaCu 3 Ti 4 O 12 (CCTO) particle-filled epoxy microwave absorbing coatings were prepared, and their electromagnetic properties and reflection loss (RL) were investigated in the frequency range 8.2-12.4 GHz. The microstructures of these coatings exhibit a uniform dispersion of MWCNTs and CCTO particles in the matrix. The value and frequency dependency of complex permittivity of such coatings enhanced with increasing MWCNT content. Frequencyselective surface was used to improve their microwave absorption (both the operating bandwidth and minimum RL) without increasing the absorber thickness. Such absorber showed high microwave absorbing performance, and the bandwidth of the RL below -8 dB (more than 84.1 % absorption) can be obtained in the whole X-band with a thickness of 1.5 mm.

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“…For a metal-backed microwave-absorbing layer under normal incidence, the RL is given by following relation [28]:…”

Section: Microwave Absorption Of the Cctoand Mwcnt-filled Compositesmentioning

confidence: 99%

CaCu3Ti4O12 particles and MWCNT-filled microwave absorber with improved microwave absorption by FSS incorporation

et al. 2016

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“…We demonstrated the high purity of the iron product obtained [7], but did not study the micro-morphology of this iron. Particle size and morphology are critical characteristics in a variety of metal and metal oxide applications including catalysis, epoxy composites, MRI, drug delivery, magnetic separation, and immobilization of biosubstances [21][22][23]. In catalytic reactions, the size of the catalyst is one of the factors to affect its catalytic efficiency [24,25].…”

Section: Introductionmentioning

confidence: 99%

Sustainable Electrochemical Synthesis of Large Grain- or Catalyst-Sized Iron

Wang

Licht

2016

J. Sustain. Metall.

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Electrolytic production of iron in molten salts by splitting iron oxide into iron metal and O 2 is a low-carbon footprint alternative to the massive CO 2 emissions associated with conventional carbothermal iron production and permits. This study advances a CO 2 -free method for iron production, by modifying iron electrosynthesis in molten Li 2 CO 3 to control iron product particle size and by decreasing the electrolyte extracted with the pure iron product. We present the first study of electrolytic iron micro-morphology as formed from iron, and demonstrate it is strongly influenced by the deposition conditions. Particle size and morphology are critical characteristics in a variety of metal applications. In this study, large (*500 lm) iron particles are formed at low current densities during extended electrolysis, or at high Fe(III) concentrations, and small (*10 lm) at high current density and low Fe(III). Deposited Fe is fiber shaped from equal molals of Fe 2 O 3 and Li 2 O, but particle-like from electrolytes with surplus Li 2 O. Iron is formed at high current efficiency, and the observed electrolysis potential decreases with (i) the decreasing current density, (ii) addition of Li 2 O, (iii) the increasing anode area, and (iv) the increasing temperature.

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“…Generally, the absorbent fillers were dispersed in epoxy resin as coating for application. 10,11 Recently, there are several reports about the microwave absorber composites of the absorbent particles dispersed in polymer matrix, 12 which showed good absorbing properties, but the total thickness of the absorber is no less than 1mm. Bailly et al 13 reported a novel multilayer structure composed of alternating dielectric polymer film and conducting layers with thickness of 4mm, which can effectively absorb electromagnetic wave radiation in a broad range.…”

Section: Introductionmentioning

confidence: 99%

Influence of external magnetic field on the microwave absorption properties of carbonyl iron and polychloroprene composites film

Wang

2016

AIP Advances

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The carbonyl iron particles were dispersed in a polychloroprene rubber (CR) matrix under a magnetic field for a practical application as microwave absorption composites film. In comparison with the carbonyl iron particles (CIP)/CR composites film prepared by general route, such films made with external magnetic field exhibit excellent microwave absorption properties, strongly depending on the increment of anisotropy and rearrangement of magnetic particles. The film made under external magnetic field with a thickness of only 0.54 mm shows least reflection loss of -15.98 dB and the reflection loss value less than -10.0 dB over the frequency range of 11.4∼14.8 GHz. The results indicated the composite film made under external magnetic field have excellent microwave absorption properties, which suggest that the composites thin film could be used as a thinner and lighter microwave absorber.

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Graphene nanosheet- and flake carbonyl iron particle-filled epoxy–silicone composites as thin–thickness and wide-bandwidth microwave absorber

Cited by 293 publications

References 57 publications

CaCu3Ti4O12 particles and MWCNT-filled microwave absorber with improved microwave absorption by FSS incorporation

CaCu3Ti4O12 particles and MWCNT-filled microwave absorber with improved microwave absorption by FSS incorporation

Sustainable Electrochemical Synthesis of Large Grain- or Catalyst-Sized Iron

Influence of external magnetic field on the microwave absorption properties of carbonyl iron and polychloroprene composites film

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