Investigation of the Microwave Absorption Properties of Fe Based Nanocomposites

2021 ◽  
Vol 407 ◽  
pp. 96-105
Author(s):  
Fadhéla Otmane ◽  
Salim Triaa ◽  
Zineb Hamlati ◽  
Ridha Boumagouda ◽  
Farid Kara
Keyword(s):  
Magnetic Loss ◽  
High Energy ◽  
Milling Process ◽  
Electromagnetic Properties ◽  
Resin Matrix ◽  
Absorption Characteristic ◽  
Relative Dielectric Permittivity ◽  
Microwave Absorption Properties ◽  
Wave Guides ◽  
Metallic Waveguide

The objective of this work was to provide information about the behaviour of Fe-based nanocomposites when exposed to microwaves. It is about rectangular bulk samples of epoxy resin reinforced by nanocrystalline Fe powders and shaped in accordance to the internal section of the R100 metallic waveguide (8.2 to 12.4 GHz) at a fixed thickness of 7 mm. The nanocrystalline Fe powders were obtained by high-energy mechanical milling process using a planetary Retsch PM 400-ball mill. The milling speed was fixed at 200 rpm for three durations and the milling process were performed under Argon atmosphere. The bulk nanocomposites were obtained by dispersion of 30% vol. of the nanocrystalline Fe powders in the resin matrix. Electromagnetic parameters as complex relative dielectric permittivity and magnetic permeability, electric and magnetic loss tangent and reflection loss were calculated using reordered S parameters. The scattering parameters were characterized using a measure cell made off two metallic R100 wave-guides associated to an Agilent 8719 network analyser according to the reflection-transmission technique. The obtained spectra inform on the new electromagnetic properties as well as the absorption characteristic acquired by the bulk nanocomposites due to the presence of the nanocrystalline Fe powders.

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.

Microwave Absorption Properties of Fe3O4-Graphene Nanohybrids

2017 ◽  
Vol 268 ◽  
pp. 297-301 ◽  
Author(s):  
Yau Thim Ng ◽  
Wei Kong ◽  
Sivanesan Appadu ◽  
Ing Kong
Keyword(s):  
Microwave Absorption ◽  
Magnetic Loss ◽  
Impedance Matching ◽  
Low Frequency ◽  
Electromagnetic Properties ◽  
Frequency Range ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
In Situ Deposition

Magnetite (Fe3O4)-graphene nanohybrids having three different weight ratios of magnetite to graphene were synthesized by a facile in-situ deposition method. The combination of dielectric properties of graphene and magnetic properties of magnetite makes the nanohybrids an ideal choice of material for microwave absorption applications. In regards to that, the electromagnetic properties and microwave absorbing characteristics were investigated in a frequency range of 1-18 GHz. The reflection loss (RL) reaches a minimum of-40.44 dB at 6.84 GHz with a thickness of 7 mm for the sample containing 73 wt·% of Fe3O4. The bandwidth corresponding to the RL below-10 dB is 7.05 GHz. The as-prepared Fe3O4-graphene nanohybrids showed good microwave absorption ability in the low frequency band (C-band) which can be ascribed to improved impedance matching characteristics, enhanced interfacial polarizations as well as the magnetic loss contributions. Moreover, the frequency related to minimum RL could be tuned by varying the weight ratios of magnetite to graphene.

scholarly journals Coir Fibers Treated with Henna as a Potential Reinforcing Filler in the Synthesis of Polyurethane Composites

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1128
Author(s):  
Sylwia Członka ◽  
Anna Strąkowska ◽  
Agnė Kairytė
Keyword(s):  
Mechanical Properties ◽  
High Energy ◽  
Dynamic Mechanical Properties ◽  
Milling Process ◽  
Coir Fiber ◽  
Lawsonia Inermis ◽  
Coir Fibers ◽  
Mechanical Performances ◽  
The Impact ◽  
Reinforcing Filler

In this study, coir fibers were successfully modified with henna (derived from the Lawsonia inermis plant) using a high-energy ball-milling process. In the next step, such developed filler was used as a reinforcing filler in the production of rigid polyurethane (PUR) foams. The impact of 1, 2, and 5 wt % of coir-fiber filler on structural and physico-mechanical properties was evaluated. Among all modified series of PUR composites, the greatest improvement in physico-mechanical performances was observed for PUR composites reinforced with 1 wt % of the coir-fiber filler. For example, on the addition of 1 wt % of coir-fiber filler, the compression strength was improved by 23%, while the flexural strength increased by 9%. Similar dependence was observed in the case of dynamic-mechanical properties—on the addition of 1 wt % of the filler, the value of glass transition temperature increased from 149 °C to 178 °C, while the value of storage modulus increased by ~80%. It was found that PUR composites reinforced with coir-fiber filler were characterized by better mechanical performances after the UV-aging.

Preparation of graphene oxide by dry planetary ball milling process from natural graphite

RSC Advances ◽  
2016 ◽  
Vol 6 (15) ◽  
pp. 12657-12668 ◽  
Author(s):  
Pranita Dash ◽  
Tapan Dash ◽  
Tapan Kumar Rout ◽  
Ashok Kumar Sahu ◽  
Surendra Kumar Biswal ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Ball Milling ◽  
High Energy ◽  
Milling Process ◽  
Graphene Oxides ◽  
Natural Graphite ◽  
Ball Milling Process ◽  
Planetary Ball Milling

Graphene oxides (GO) with different degrees of oxidation have been prepared by an in-house designed horizontal high energy planetary ball milling process.

Elaboration and Characterization of Cu Based Nanocomposites for Electromagnetic Interferences Shielding

2021 ◽  
Vol 412 ◽  
pp. 177-184
Author(s):  
Farid Kara ◽  
Fadhéla Otmane ◽  
Samir Bellal ◽  
Amira Djenet Guerfi ◽  
S. Triaa
Keyword(s):  
Epoxy Resin ◽  
Xrd Analysis ◽  
High Energy ◽  
Shielding Effectiveness ◽  
Emi Shielding ◽  
Emi Shielding Effectiveness ◽  
Cell Measurement ◽  
Wave Guides ◽  
Pure Cu ◽  
Thin Samples

An electromagnetic interferences (EMI) shielding is a material that attenuates radiated electromagnetic energy. Polymer nanocomposites is a class of materials that combine electrical, thermal, dielectric, magnetic and/ or mechanical properties, which are useful for the suppression of electromagnetic interferences. In this work, we looked over the effectiveness of the electromagnetic interferences shielding of polymer-based nanocomposites. These are thin samples of epoxy resin strengthened with nanostructured Cu powders. Nanostructured Cu powders were obtained by mechanical milling using the high-energy RETSCH PM400 ball mill (200 rpm). A powder sampling was conducted after 3h, 6h, 12h, 24h, 33h, 46h and 58h milling for characterization requirements. XRD analysis via the Williamson-Hall method shows that the mean crystallites size decreases from 151.6 nm (pure Cu phase) to 13.8 nm (58 h milling). Simultaneously, the lattice strain increases from 0.1% (pure Cu phase) to 0.59% (58 h milling). The elaboration of thin samples was performed by mixing a vol./3 fractions of nanostructured Cu powder, epoxy resin and hardener. Thin slabs of 1 mm thickness were moulded for use in a rectangular wave-guide. The EMI shielding experimental involved a two ports S parameters cell measurement made of R120 metallic wave-guides of rectangular section (19.05x9.525 mm2) and operational over the frequency band of 9.84 to 15 GHz associated to a network analyser. Obtained results show moderate EMI shielding effectiveness for the milled Cu-based slabs.

scholarly journals The Structural Evolution of Al86Ni9La5 Glassy Ribbons during Milling at Room and Cryogenic Temperatures

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1956
Author(s):  
Zhicheng Yan ◽  
Yan Liu ◽  
Shaopeng Pan ◽  
Yihua Hu ◽  
Jing Pang ◽  
...  
Keyword(s):  
Milling Time ◽  
Shear Bands ◽  
Structural Evolution ◽  
High Energy ◽  
Milling Process ◽  
Cryogenic Temperatures ◽  
Dynamic Simulations ◽  
Tricapped Trigonal Prism ◽  
Medium Range ◽  
Energy Ball

Melt-spun metallic Al86Ni9La5 glassy ribbons solidified at different circumferential speeds (Sc) were subjected to high-energy ball milling at room and cryogenic temperatures. Crystallization induced by milling was found in the Al86Ni9La5 solidified at lower circumferential speed (Sc = 14.7 m/s), while the Al86Ni9La5 with Sc = 36.6 m/s kept amorphous. Besides, a trend of structural rejuvenation during milling process was observed, as the onset temperatures (Tx1, Tx2) and the crystallization enthalpies (ΔH1, ΔH2) first decreased and then increased along with the milling time. We explored the structural origin of crystallization by ab initio molecular dynamic simulations and found that the tricapped trigonal prism (TTP) Ni-centered clusters with a higher frequency in samples solidified at a lower cooling rate, which tend to link into medium-range orders (MROs), may promote crystallization by initiating the shear bands during milling. Based on the deformation mechanism and crush of metallic glasses, we presented a qualitative model to explain the structural rejuvenation during milling.

High-Energy Ball Milling and Sintering of Ti-2Ta-22Si-11B and Ti-6Ta-22Si-11B Powders Mixtures

2014 ◽  
Vol 802 ◽  
pp. 20-24 ◽  
Author(s):  
Lucas Moreira Ferreira ◽  
Luciano Braga Alkmin ◽  
Érika C.T. Ramos ◽  
Carlos Angelo Nunes ◽  
Alfeu Saraiva Ramos
Keyword(s):  
Ball Milling ◽  
Weight Ratio ◽  
High Energy ◽  
Milling Process ◽  
Wet Milling ◽  
X Ray Diffraction ◽  
Heat Treated ◽  
Equilibrium Structures ◽  
Rotary Speed ◽  
Steel Balls

The milling process of elemental Ti-2Ta-22Si-11B and Ti-6Ta-22Si-11B (at-%) powder mixtures were performed in a planetary Fritsch P-5 ball mill using stainless steel vials (225 mL) and hardened steel balls (19 mm diameter). Ball-to-powder weight ratio of 10:1 and a rotary speed of 300 rpm were adopted, varying the milling time. Wet milling (isopropyl alcohol) for 20 more minutes was used to increase the yield powder in to the vial. Following the Ti-Ta-Si-B powders milled for 600 min were heat-treated at 1100°C for 1 h in order to obtain the equilibrium structures. The milled powders and heat-treated samples were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. Supersaturated Ti solid solutions were formed during ball milling of Ti-Ta-Si-B powders while that the Ti5Si3 phase was formed after milling for 620 min of the Ta-richer powder mixture only. The particles sizes were initially increased during the initial milling times, and the wet milling provided the yield powder into the vials. A large amount of pores was found in both the sintered samples which presented the formation of the TiSS,(ss-solid solution) Ti6Si2B and TiB.

scholarly journals Influence of ZnO addition and milling process on structure and conductivity of BaCe0.2Zr0.7Y0.1O3-δ ceramics

2021 ◽  
Vol 15 (3) ◽  
pp. 288-296
Author(s):  
Ana Ana Kaori de Oliveira Ouba ◽  
Adilson Chinelatto ◽  
Edson Grzebielucka ◽  
Kethlinn Ramos ◽  
Janaina Borcezi ◽  
...  
Keyword(s):  
Secondary Phase ◽  
Linear Shrinkage ◽  
High Energy ◽  
Milling Process ◽  
Sintering Aids ◽  
X Ray Diffraction ◽  
Sintering Aid ◽  
Secondary Phase Formation ◽  
Precursor Powders ◽  
Perovskite Lattice

Precursor powders for BaCe0.2Zr0.7Y0.1O3-?(BCZY27) ceramics were synthesized by a modified Pechinimethod and calcined at 900?C for 12 h. The calcined BCZY27 powders were milled in eccentric and in high energy mill with the addition of 2 and 4mol% ZnO as sintering aid. The effects of milling and sintering aids on the sinterability and electrical conductivity were studied. The linear shrinkage in thermomechanical analyses started at 1050?C for the BCZY27 with 4mol% ZnO processed in eccentric mill. Theoretical density above of 90%TD was obtained for the BCZY27 milled with 4mol% ZnO and sintered at 1400?C for 4h. X-ray diffraction analysis of the BCZY27 ceramics sintered at 1400?C confirmed the presence of BaCe0.2Zr0.7Y0.1O3-? and Y0.4Ce0.6O1.8 phases. The incorporation of Zn into perovskite lattice leads to the secondary phase formation. SEM and EDS analyses confirmed the presence of Y0.4Ce0.6O1.8 phase. The sintering was assisted by BaO-ZnO eutectic, which was reflected by the increase of activation energy values for grain boundary conduction. The milling processing did not affect the conductivity properties. The obtained BCZY27 dense sample has conductivity of 7.60 ? 10?3 S/cm at 500?C.

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