Electromagnetic wave absorbing properties and hyperfine interactions of Fe—Cu—Nb—Si—B nanocomposites

Abstract

The Fe-Cu-Nb-Si-B alloy nanocomposite containing two ferromagnetic phases (amorphous phase and nanophase phase) is obtained by properly annealing the as-prepared alloys. High resolution transmission electron microscopy (HRTEM) images show the coexistence of these two phases. It is found that Fe-Si nanograins are surrounded by the retained amorphous ferromagnetic phase. Mossbauer spectroscopy measurements show that the nanophase is the D0 3 -type Fe-Si phase, which is employed to find the atomic fractions of resonant 57Fe atoms in these two phases. The microwave permittivity and permeability spectra of Fe-Cu-Nb-Si-B nanocomposite are measured in the frequency range of 0.5 GHz-10 GHz. Large relative microwave permeability values are obtained. The results show that the absorber containing the nanocomposite flakes with a volume fraction of 28.59% exhibits good microwave absorption properties. The reflection loss of the absorber is less than −10 dB in a frequency band of 1.93 GHz-3.20 GHz. KeywordsMossbauer spectroscopy, magnetic permeability, nanocrystalline alloys Disciplines Electrical and Computer Engineering | Electromagnetics and Photonics

Enhancing the Microwave Absorption Properties of Fe–Cu–Nb–Si–B Nanocomposite Flakes by Coating With Spinel Ferrite NiFe2O4

“…And the calculated average grain sizes of them are 3.79 nm and 14.01 nm, respectively. In our previous work, the nano-grain size measured by TEM is 14.38 nm and the content of α-Fe 3 Si phase in the uncoated flakes which has obtained by Mössbauer spectroscopy measurement is 57.365 % [12,15]. By comparing with these results, the validity of our XRD refinement is confirmed.…”

“…(2). For both samples, three obvious diffraction peaks are found, which are associated with (220), (400) and (422) planes, to indicate that nanocrystalline phase (Fe 3 Si) with a DO 3 type superlattice structure for the flakes [12]. The spinel ferrite phase (NiFe 2 O 4 ) also can be identified by their diffraction peaks (220), (311) and (400) in the XRD pattern of coated particles, which manifest that the spinel ferrite NiFe 2 O 4 is successfully coated on the flakes via the low temperature co-precipitation method.…”

Studies on the microwave permittivity and electromagnetic wave absorption properties of Fe-based nano-composite flakes in different sizes

“…The studies on the phase transitions due to the annealing treatment have already been investigated by our previous report. 25 The morphologies of two classes of particles are shown in Figs. 1(b) and 1(c).…”

Study of structural and magnetic properties of Fe 80 P 9 B 11 amorphous alloy by ab initio molecular dynamic simulation

“…Due to their excellent soft magnetic property and low cost, Fe-based metallic glasses have captured much attention experimentally and theoretically. [1][2][3][4][5][6] Metallic glasses are generally produced by rapid cooling methods, where the viscosity increases exponentially until glass transition occurs. [7] Egami et al put forward the concept of atomic level stress, and described the glass transition in terms of topological instability.…”