Microwave Absorption Properties of Fe40Co60 Based Nanocomposites

2021 ◽  
Vol 413 ◽  
pp. 209-216
Author(s):  
Ridha Boumagouda ◽  
Fadhéla Otmane ◽  
Zineb Hamlati ◽  
Samir Bellal ◽  
Sabrina Zeghdoud ◽  
...  
Keyword(s):  
Grain Size ◽  
Microwave Absorption ◽  
Resonant Cavity ◽  
High Energy ◽  
Soft Magnetic Materials ◽  
Resin Matrix ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Processing Technologies ◽  
Size Refinement

Microwave absorbing materials are applied in stealth, communications and information processing technologies. This kind of material dissipates an electromagnetic wave by converting it into thermal energy. The nanostructuration of materials became a reliable route over the years to enhance the dielectric and magnetic properties, which induce the required interaction. Nanostructured Fe-Co alloys are soft magnetic materials that make them promising candidates for microwave absorption when combined with other materials. The aim of our study was therefore to investigate the microwave absorption properties of based nanocomposites. The nanocomposites were obtained by the solution dispersion method. Nanocrystalline alloys elaborated by mechanical alloying (MA) in a high-energy planetary ball mill (RETSCH PM400) were dispersed into commercial epoxy resin matrix to form thin polymer nanocomposites. The grain size refinement and structural properties changes during milling process were characterized using powder’s X-ray Diffraction (XPERT PRO MPD diffractometer) at different milling durations. XRD spectra analysis show that a grain size refinement of 4.54 nm was reached after 60h milling accompanied with 1.2 % microdeformations. Obtained powders were shaped in small discs for which resonant cavity measurements were undertaken. The based nanocomposites have been subject to an experiment of two-port S parameters measurement in a rectangular waveguide (R120). The microwave experiments involved a Network Analyzer (VNA). Obtained results in terms of reflection losses show a good absorbing characteristic over the [8-15] GHz microwaves band.

EFFECT OF Nd-DOPING ON THE NANOCRYSTALLITE SIZE AND MICROWAVE ABSORPTION PROPERTIES OF Sr-HEXAFERRITE

2011 ◽  
Vol 04 (03) ◽  
pp. 283-287 ◽  
Author(s):  
H. KHANMOHAMMADI ◽  
S. A. SEYYED EBRAHIMI
Keyword(s):  
Crystallite Size ◽  
Microwave Absorption ◽  
Average Crystallite Size ◽  
Strontium Hexaferrite ◽  
Resin Matrix ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Calcination Temperatures ◽  
Nanocrystallite Size ◽  
Scherrer Formula

Nd -doped M -type Strontium hexaferrite powders with composition of Sr 1-x Nd x Fe 12 O 19(x = 0, 0.1, 0.2) were prepared by conventional ceramic method at various calcination temperatures. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used for characterization of the obtained powders. The results showed that by increasing Nd doping, the single phase magnetoplumbite structure has been formed at higher temperatures. The average crystallite size of the samples calculated by the Scherrer formula indicates that Nd -doping resulted in a significant decrease in the mean crystallite size. The hexaferrite-polymer bulk composites in epoxy resin matrix, with ferrite ratio of 90 wt.%, were also prepared. The microwave absorption properties of these composites were investigated in 8–12 GHz frequency range by means of a vector network analyzer. Due to the reflection loss measurements, Nd -doped Sr -hexaferrite could be a promising material for microwave absorption applications in X-band.

scholarly journals Complex Permittivity and Microwave Absorption Properties of OPEFB Fiber–Polycaprolactone Composites Filled with Recycled Hematite (α-Fe2O3) Nanoparticles

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 918 ◽  
Author(s):  
Ebenezer Ekow Mensah ◽  
Zulkifly Abbas ◽  
Raba’ah Syahidah Azis ◽  
Nor Azowa Ibrahim ◽  
Ahmad Mamoun Khamis
Keyword(s):  
Microwave Absorption ◽  
Complex Permittivity ◽  
Microstructural Analysis ◽  
High Energy ◽  
Fe2o3 Nanoparticles ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Transmission Electron ◽  
Line Measurement

Recycled hematite (α-Fe2O3) nanoparticles with enhanced complex permittivity properties have been incorporated as a filler in a polycaprolactone (PCL) matrix reinforced with oil palm empty fruit bunch (OPEFB) fiber for microwave absorption applications. The complex permittivity values were improved by reducing the particle sizes to the nano scale via high-energy ball milling for 12 h. A total of 5–20 wt.% recycled α-Fe2O3/OPEFB/PCL nanocomposites were examined for their complex permittivity and microwave absorption properties via the open ended coaxial (OEC) technique and the transmission/reflection line measurement using a microstrip connected to a two-port vector network analyzer. The microstructural analysis of the samples included X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR). At 1 GHz, the real (ε′) and imaginary (ε″) parts of complex permittivity of recycled α-Fe2O3 particles, respectively, increased from 7.88 to 12.75 and 0.14 to 0.40 when the particle size was reduced from 1.73 μm to 16.2 nm. A minimum reflection loss of −24.2 dB was achieved by the 20 wt.% nanocomposite at 2.4 GHz. Recycled α-Fe2O3 nanoparticles are effective fillers for microwave absorbing polymer-based composites in 1–4 GHz range applications.

Preparation and Microwave Absorption Properties of LiZn Ferrite

2009 ◽  
Vol 25 (1) ◽  
pp. 73-76 ◽  
Author(s):  
Hong JIANG ◽  
Jia GUO ◽  
Lu ZHAO ◽  
Hong ZHU
Keyword(s):  
Microwave Absorption ◽  
Absorption Properties ◽  
Microwave Absorption Properties

scholarly journals Effect of Reaction Time on Microwave Absorption Properties of Fe3O4 Hollow Spheres Synthesized via Ostwald Ripening

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2921 ◽  
Author(s):  
Wei Huang ◽  
Yujiang Wang ◽  
Shicheng Wei ◽  
Bo Wang ◽  
Yi Liang ◽  
...  
Keyword(s):  
Reaction Time ◽  
Microwave Absorption ◽  
Ostwald Ripening ◽  
Impedance Matching ◽  
Hollow Spheres ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Magnetic Structures ◽  
Absorption Performance ◽  
Microwave Absorption Performance

Hollow magnetic structures have great potential to be used in the microwave absorbing field. Herein, Fe3O4 hollow spheres with different levels of hollowness were synthesized by the hydrothermal method under Ostwald ripening effect. In addition to their microstructures, the microwave absorption properties of such spheres were investigated. The results show that the grain size and hollowness of Fe3O4 hollow spheres both increase as the reaction time increases. With increasing hollowness, the attenuation ability of electromagnetic wave of Fe3O4 spheres increases first and then decreases, finally increases sharply after the spheres break down. Samples with strong attenuation ability can achieve good impedance matching, which it does preferentially as the absorber thickness increases. Fe3O4 hollow spheres show the best microwave absorption performance when the reaction time is 24 h. The minimum reflection loss (RL (min)) can reach −40 dB, while the thickness is only 3.2 mm.

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