EM-wave absorption properties of hollow spiral iron particles
Introduction
With the rapid advancement of wireless communication technologies, electromagnetic wave (EM-wave) absorbing materials, as a new type of function material, have become increasingly valued in both military application and civil use [1], [2], [3], [4], [5], [6], [7], [8], [9]. The EM-wave absorbing particles play a key role in EM-wave absorbing materials. Carbonyl iron powder and polycrystalline iron fiber have been considered as quality materials with highly efficient absorbing properties, and they were generally fabricated by thermal decomposition of the carbonyl compounds [5]. However, it is difficult to make a breakthrough in the performance of these materials, especially in meeting the demands for thinner but wider, lighter but stronger materials. As new absorbing materials, chiral materials and composite structures [6], which have recently attracted much attention, have much potential for further development and application. A new type of high-quality EM-wave absorbent is likely via combining spirulina, a product characterized by a natural chiral structure, with the magnetic absorbing material. In this paper, hollow iron spiral particles were synthesized by a thermal decomposition method, and the EM-wave absorption properties were investigated in detail.
Section snippets
Material and methods
First, this study used cells of spirulina platens (spirulina platensis, Nordst. Geitl.), a blue–green microorganism of natural helical shape, as forming templates. Generally, its helix was 26–36 μm in width, with a distance of 43–57 μm between two coils and 4–7 (20 at most) helixes. These spirulina cells were preserved with glutaraldehyde before thermal decomposition process in order to keep their initial shape [1].
Secondly, weigh the needed spirulina (1 g) and dehydrate it with ethanol before
Results and discussion
Fig. 1 shows the images of iron coated on the Spirulina by thermal decomposition method. It is found that the surface was rough, but was magnetic, and kept the hollow helical shape very well. The thickness of coating layers is about 250 nm. Further, the EDS analysis results show that the main component of the particle is pure iron, which means the iron spiral particles were prepared successfully.
The permeability and EM-wave absorbing properties would be affected by the crystalline structure of
Conclusions
Hollow iron spiral particles have been successfully prepared by a thermal decomposition method. The phase structures of the particles changed from amorphous to nanocrystals after heat-treatment at 400 °C, and the crystal size increased with the temperature rising, resulting in the obvious change of the electromagnetic parameters. The iron spiral particles showed high RL properties.
Acknowledgments
This work was supported by the National Natural Science Foundation of China (Grant no. 51305446), the National “863” Project of China (Grant no. 2009AA043804). The authors would like to thank Gangxu Yong from Beihang University for EM-parameter test of the samples.
References (10)
- et al.
Appl. Surf. Sci.
(2014) - et al.
J. Magn. Magn. Mater.
(2002) - et al.
Sci. China Ser. E-Tech Sci.
(2003) - et al.
Chin. Sci. Bull.
(2003) - et al.
Sci. China Ser. E-Tech Sci.
(2008)
Cited by (12)
Preparation and electromagnetic wave absorption properties of hollow Co, Fe@air@Co and Fe@Co nanoparticles
2018, Advanced Powder TechnologyCitation Excerpt :Importantly, many efforts have been devoted to obtaining the desired EM wave absorption properties with thin thickness and broad effective bandwidth. It has been proved that, the structure [18], morphology [19], and shell thickness [20] of materials with core-shell structure are significant in enhancing EM wave absorption properties. But so far, there is still no one pay attention to the effect of relationship between core and shell on EM wave absorption properties of bimetallic magnetic core-shell materials.
Improved magnetic and microwave absorption properties of manganese nitrides through the addition of ferrous
2017, Journal of Alloys and CompoundsCitation Excerpt :During the last few years, increasing attention has been focused on microwave absorption materials (MAM) due to the more serious electromagnetic pollution, electromagnetic inteference, and urgent military demanding. Magnetic metals and alloys [1,2] ferrite [3,4]s, nonferrite ceramics [5,6] carbon materials [7,8], polymers [9,10] and hybrid materials [11,12] have been studied as MAM. Among the nonferrite ceramics MAM, 3d transition metal nitrides powders such as manganese nitrides [13–15], have attracted more and more attention because they have excellent magnetic, electric, hard, durable, abrasive-resistant, low cost and stable chemical properties [16,17].
The microwave absorption properties of carbon-encapsulated nickel nanoparticles/silicone resin flexible absorbing material
2016, Journal of Alloys and CompoundsCitation Excerpt :However, it also brings a serious problem, i.e., electromagnetic interference (EMI), which endangers microwave communications, aerospace facilities, sophisticated weapon systems and human health [2]. It is high time that we should develop some effective absorbents with the characteristics of wide bandwidth, strong absorption, tunable electromagnetic properties, and high reliability to solve it [3,4]. In the past decades, researchers have made a lot of work in searching suitable absorbents, and the metallic soft magnetic materials are the most representative, due to their high saturation magnetization and higher Snoek’s limit at frequency over gigahertz [5].
Combined use of lightweight magnetic Fe<inf>3</inf>O<inf>4</inf>-coated hollow glass spheres and electrically conductive reduced graphene oxide in an epoxy matrix for microwave absorption
2016, Journal of Magnetism and Magnetic MaterialsCitation Excerpt :With the rapid development of electronic devices and microwave communication equipment, electromagnetic radiation has become increasingly serious. As a result, protecting person's health from electromagnetic radiation and protecting information security from electromagnetic wave leaking have become a serious concern [1,2]. A high-performance microwave absorber can eliminate such adverse electromagnetic radiation effectively.
Synthesis of multilayered micro flower NiCo<inf>2</inf>O<inf>4</inf>/GN/Fe<inf>3</inf>O<inf>4</inf> composite for enhanced electromagnetic microwave (EM) absorption performance
2019, Journal of Materials Science: Materials in ElectronicsSynthesis of rGO/p-Fe<inf>3</inf>O<inf>4</inf>@PANI three-phase nanomaterials and electromagnetic wave absorption properties
2019, Materials Research Express