scholarly journals Structural, Electromagnetic and Microwave Properties of Magnetite Extracted from Mill Scale Waste via Conventional Ball Milling and Mechanical Alloying Techniques

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7075
Author(s):  
Madiha Fathi Elmahaishi ◽  
Raba’ah Syahidah Azis ◽  
Ismayadi Ismail ◽  
Muhammad Syazwan Mustaffa ◽  
Zulkifly Abbas ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Ball Milling ◽  
Microwave Absorption ◽  
Magnetic Separation ◽  
Reflection Loss ◽  
Impedance Matching ◽  
High Energy ◽  
Absorption Properties ◽  
Mill Scale ◽  
Magnetite Fe3o4

This study presents the utilization of mill scale waste, which has attracted much attention due to its high content of magnetite (Fe3O4). This work focuses on the extraction of Fe3O4 from mill scale waste via magnetic separation, and ball milling was used to fabricate a microwave absorber. The extracted magnetic powder was ground-milled using two different techniques: (i) a conventional milling technique (CM) and (ii) mechanical alloying (MM) process. The Fe3O4/CM samples were prepared by a conventional milling process using steel pot ball milling, while the Fe3O4/MM samples were prepared using a high-energy ball milling (HEBM) method. The effect of milling time on the structural, phase composition, and electromagnetic properties were examined using X-ray diffraction (XRD) and a vector network analyzer (VNA). XRD confirmed the formation of magnetite after both the magnetic separation and milling processes. The results revealed that Fe3O4 exhibited excellent microwave absorption properties because of the synergistic characteristics of its dielectric and magnetic loss. The results showed that the Fe3O4/CM particle powder had a greater absorption power (reflection loss: <−10 dB) with 99.9% absorption, a minimum reflection loss of −30.83 dB, and an effective bandwidth of 2.30 GHz for 2 mm thick samples. The results revealed the Fe3O4/MM powders had higher absorption properties, including a higher RL of −20.59 dB and a broader bandwidth of 2.43 GHz at a matching thickness of only 1 mm. The higher microwave absorption performance was attributed to the better impedance matching property caused by the porous microstructure. Furthermore, the magnetite, Fe3O4 showed superior microwave absorption characteristics because of the lower value of permittivity, which resulted in better impedance matching. This study presents a low-cost approach method by reutilizing mill scale waste to fabricate a high purity crystalline Fe3O4 with the best potential for designing magnetic nano-sized based microwave absorbers.

scholarly journals Structural, microstructural, magnetic and electromagnetic absorption properties of spiraled multiwalled carbon nanotubes/barium hexaferrite (MWCNTs/BaFe12O19) hybrid

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nurshahiera Rosdi ◽  
Raba’ah Syahidah Azis ◽  
Ismayadi Ismail ◽  
Nurhidayaty Mokhtar ◽  
Muhammad Misbah Muhammad Zulkimi ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Microwave Absorption ◽  
Multiwalled Carbon Nanotubes ◽  
Reflection Loss ◽  
Barium Hexaferrite ◽  
High Energy ◽  
Absorption Properties ◽  
Multiwalled Carbon ◽  
Absorption Bandwidth ◽  
Minimum Reflection Loss

AbstractMicrowave absorption properties were systematically studied for synthesised barium hexaferrite (BaFe12O19) nanoparticles and spiraled multiwalled carbon nanotubes (MWCNTs) hybrid. BaFe12O19 nanoparticles were synthesised by a high energy ball milling (HEBM) followed by sintering at 1400 °C and structural, electromagnetic and microwave characteristics have been scrutinized thoroughly. The sintered powders were then used as a catalyst to synthesise spiraled MWCNTs/BaFe12O19 hybrid via the chemical vapour deposition (CVD) process. The materials were then incorporated into epoxy resin to fabricate single-layer composite structures with a thickness of 2 mm. The composite of BaFe12O19 nanoparticles showed a minimum reflection loss is − 3.58 dB and no has an absorption bandwidth while the spiraled MWCNTs/BaFe12O19 hybrid showed the highest microwave absorption of more than 99.9%, with a minimum reflection loss of − 43.99 dB and an absorption bandwidth of 2.56 GHz. This indicates that spiraled MWCNTs/BaFe12O19 hybrid is a potential microwave absorber for microwave applications in X and Ku bands.

scholarly journals Excellent Microwave Absorption Properties Derived from the Synthesis of Hollow Fe3o4@Reduced Graphite Oxide (RGO) Nanocomposites

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 141 ◽  
Author(s):  
Guangzhen Cui ◽  
Yanli Lu ◽  
Wei Zhou ◽  
Xuliang Lv ◽  
Jiangnan Hu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Graphite Oxide ◽  
Photoelectron Spectroscopy ◽  
Impedance Matching ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
X Ray ◽  
Reduced Graphite Oxide

Magnetic nanoparticles, such as Fe3O4 and Co3O4, play a vital role in the research on advanced microwave absorbing materials, even if problems such as high density and narrow band impedance matching are still unsolved. Herein, the study of lightweight hollow Fe3O4@reduced graphite oxide (RGO) nanocomposites synthesized via the solvothermal method is presented. The microstructure and crystal morphology of the materials were characterized by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analyses. Single crystalline hollow Fe3O4 spheres were grown onto RGO flakes, leading to the formation of heterojunction, which further influenced the microwave absorption properties. The latter were evaluated by standard microwave characterization in the frequency range of 2–18 GHz. It was found that, for a specific [email protected] g RGO composite, the minimum reflection loss can reach −41.89 dB at 6.7 GHz, while the reflection loss was less than −10 dB from 3.4 GHz to 13.6 GHz for a nanocomposite sample thickness in the range of 1–4 mm. The combination of these two materials thus proved to give remarkable microwave absorption properties, owing to enhanced magnetic losses and favorable impedance matching conditions.

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.

The synergistic effects of carbon coating and micropore structure on the microwave absorption properties of Co/CoO nanoparticles

2016 ◽  
Vol 18 (44) ◽  
pp. 30507-30514 ◽  
Author(s):  
Xiubo Xie ◽  
Yu Pang ◽  
Hiroaki Kikuchi ◽  
Tong Liu
Keyword(s):  
Microwave Absorption ◽  
Vapor Deposition ◽  
Carbon Coating ◽  
Synergistic Effects ◽  
Impedance Matching ◽  
Chemical Vapor ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Micropore Structure ◽  
Coo Nanoparticles

Microporous Co/CoO/C nanoparticles prepared by combining chemical dealloying and chemical vapor deposition methods exhibited high microwave absorption properties due to the synergistic effects of the carbon coating and the micropore structure on the impedance matching of the absorber.

Magnetization and Microwave Absorption Properties of La0.67 Sr0.33 MnO3 with Different Particle Size

2011 ◽  
Vol 374-377 ◽  
pp. 1541-1544 ◽  
Author(s):  
Yu Lan Cheng ◽  
Ping Xia ◽  
Ke Xiang Wei ◽  
Quan Bai
Keyword(s):  
Particle Size ◽  
Sinter Temperature ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Sol Gel ◽  
Frequency Range ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Measured Frequency Range ◽  
Maximum Reflection Loss

La 0.67 Sr 0.33 MnO 3 particles with different particle size have been prepared by sol-gel method. The structure, magnetization and microwave absorption properties have been investigated. The results show that the particle size can be controlled by sinter temperature. The peaks of the maximum reflection loss (RL) move to higher frequency regions with increasing particle size. The value of the maximum RL is -32 dB at 10.2GHz with a particle size of 58.5nm. The bandwidth with a RL exceeding -8dB reached 1.6GHz in the whole measured frequency range, suggesting that La 0.67 Sr 0.33 MnO 3 particles are promising for application as a wideband and strong absorption building microwave absorber.

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