Effect of annealing on electromagnetic performance and microwave absorption of spherical cobalt particles

Wen, Shulai; Liu, Y; Zhao, Xiuchen

doi:10.1088/0022-3727/48/40/405001

Cited by 12 publications

(6 citation statements)

References 52 publications

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“…These elongated conglomerates can be considered as a system of dipoles which can induce intense dipole polarization, leading to the enhancement of permittivity 48 . Additionally, the conductivity of CoNi@TiO 2 microspheres can increase greatly as the defects in the particles eliminates and the crystalline integrity improves during annealing 49 . The improved conductivity is helpful to enhance dielectric relaxation and dipole polarization, leading to the evidently increased permittivity of annealed samples.…”

Section: Resultsmentioning

confidence: 99%

Rational Construction of Uniform CoNi-Based Core-Shell Microspheres with Tunable Electromagnetic Wave Absorption Properties

Chen

Jiang

et al. 2018

Sci Rep

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Core-shell particles with integration of ferromagnetic core and dielectric shell are attracting extensive attention for promising microwave absorption applications. In this work, CoNi microspheres with conical bulges were synthesized by a simple and scalable liquid-phase reduction method. Subsequent coating of dielectric materials was conducted to acquire core-shell structured CoNi@TiO2 composite particles, in which the thickness of TiO2 is about 40 nm. The coating of TiO2 enables the absorption band of CoNi to effectively shift from Ku to S band, and endows CoNi@TiO2 microspheres with outstanding electromagnetic wave absorption performance along with a maximum reflection loss of 76.6 dB at 3.3 GHz, much better than that of bare CoNi microspheres (54.4 dB at 17.8 GHz). The enhanced EMA performance is attributed to the unique core-shell structures, which can induce dipole polarization and interfacial polarization, and tune the dielectric properties to achieve good impedance matching. Impressively, TiO2 coating endows the composites with better microwave absorption capability than CoNi@SiO2 microspheres. Compared with SiO2, TiO2 dielectric shells could protect CoNi microspheres from merger and agglomeration during annealed. These results indicate that CoNi@TiO2 core-shell microspheres can serve as high-performance absorbers for electromagnetic wave absorbing application.

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Section: Resultsmentioning

confidence: 99%

Rational Construction of Uniform CoNi-Based Core-Shell Microspheres with Tunable Electromagnetic Wave Absorption Properties

Chen

Jiang

et al. 2018

Sci Rep

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“…This may refer to the fact that the network defects and strains are decreased by treating at high temperature and so the crystallinity of ferrite is increased but the crystalline structure remained intact. 18,19 The diffraction peak at 26.311 corresponds to the (002) crystal plane of MWCNT. 17 As a result, after annealing, the CuFe 2 O 4 / MWCNT maintains the general pattern of the spinel phase and there is no impurity peak seen.…”

Section: Synthesis Of Cufe 2 O 4 Npsmentioning

confidence: 99%

Superior microwave absorption ability of CuFe₂O₄/MWCNT at whole Ku-band and half X-band

poor

Hekmatara

2023

Phys. Chem. Chem. Phys.

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“…Incorporation of cobalt in polypyrrole exhibited resistive switching and magnetism [14] and showed utility in the application of electromagnetic wave absorption [15]. Of the three prominent ferromagnetic metals, cobalt has always been considered to be special as it has high saturation magnetization and Curie temperature [16]. Also, it is known for its allotropic forms of fcc, hcp, epsilon and bcc [17].…”

Section: Introductionmentioning

confidence: 99%

Studies on Conduction Mechanism, Magnetization and Electrochemical Properties of Polythiophene-Cobalt Nanocomposites

Chandraprabha¹,

Sankarappa²,

Lokhande³

et al. 2018

JNST

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Polythiophene (PTh) was prepared by chemical oxidation and cobalt nanoparticles (Co-nps) by modified polyol process. The nanocomposites were prepared by mixing mechanically the PTh and Co-nps in the weight percentage, PTh100-xCox, x = 10, 20, 30, 40 and 50. XRD of these nanocomposites showed amorphous nature. DC conductivity variation with temperature in the range from 303 K to 473 K indicated semiconducting behavior. Conduction mechanism was found to be small polaron hopping at high temperature and 3D variable range hopping at low temperatures. Conductivity and activation energy values points out that addition of Co-nps to the PTh induces electrically insulating effect. The SQUID magnetometer measurements at 10 K and 300 K showed perfect ferromagnetic nature and magnetically softness of the composites. Cyclic voltammetry study has been carried out on all the composites and in that a composite having 30% of Co-nps measured Specific Capacitance (SC) value as high as 583.20 F/g. This can be the best candidate for capacitor applications. This is for the first time that PTh-Co nanocomposites have been thoroughly probed for structure, conduction mechanism, magnetization and supercapacitor applications.

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Effect of annealing on electromagnetic performance and microwave absorption of spherical cobalt particles

Cited by 12 publications

References 52 publications

Rational Construction of Uniform CoNi-Based Core-Shell Microspheres with Tunable Electromagnetic Wave Absorption Properties

Rational Construction of Uniform CoNi-Based Core-Shell Microspheres with Tunable Electromagnetic Wave Absorption Properties

Superior microwave absorption ability of CuFe₂O₄/MWCNT at whole Ku-band and half X-band

Studies on Conduction Mechanism, Magnetization and Electrochemical Properties of Polythiophene-Cobalt Nanocomposites

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Effect of annealing on electromagnetic performance and microwave absorption of spherical cobalt particles

Cited by 12 publications

References 52 publications

Rational Construction of Uniform CoNi-Based Core-Shell Microspheres with Tunable Electromagnetic Wave Absorption Properties

Rational Construction of Uniform CoNi-Based Core-Shell Microspheres with Tunable Electromagnetic Wave Absorption Properties

Superior microwave absorption ability of CuFe2O4/MWCNT at whole Ku-band and half X-band

Studies on Conduction Mechanism, Magnetization and Electrochemical Properties of Polythiophene-Cobalt Nanocomposites

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Superior microwave absorption ability of CuFe₂O₄/MWCNT at whole Ku-band and half X-band