Substitution effect of Me = Al, Bi, Cr and Mn to the microwave properties of polyaniline/BaMeFe11O19 for absorbing electromagnetic waves

Abstract

Polyaniline/substituted barium hexaferrites (abbreviated Pani/BaMeFe 11 O 19 , where Me=Al, Bi, Cr and Mn) composites are investigated to be potential electromagnetic wave absorber from 1 to 18 GHz frequency range. Solid-Based Polymerization method is used to prepare the samples with 10 % volume fraction of hexaferrite. The effects of iron substitution in hexaferrite composites by trivalent ions Al 3+ , Bi 3+ , Cr 3+ and Mn 3+ on permittivity, permeability and microwave absorption properties are studied. Structural and morphological investigations confirm the presence of Polyaniline and barium hexaferrite phases, which are in interaction in the composites regardless the substitution.Thermogravimetric analysis exhibits an improved thermostability when small ions (Al 3+ and Cr 3+ ) are used to substitute Fe 3+ in hexaferrite compared to the large cations substitution (Bi 3+ and Mn 3+ ), since these latter interfere between the ferrite and intermolecular interaction between Pani macromolecules. Magnetic studies show a ferromagnetic behaviour for all the composites. Saturation magnetization is mainly related to the substituting cations nature in hexaferrite which is determined using measured magnetic data. Coercivity values increase slightly due to the Pani matrix that precludes the movement of the domain wall. The EM parameters ε‫,׳‬ ‫,׳׳‪ε‬‬ µ‫׳‬and ‫׳׳‪µ‬‬ are measured using a Vector Network Analyzer. It is found that the dielectric constant increases with the addition of hexaferrite. The maximum of the magnetic losses diminishes and shifts to higher frequencies with Fe 3+ doping. These measured EM parameters are used to determine the reflexion loss for different composites.Pani/BaFe 12 O 19 composite shows two minimum reflection losses (RL) in Ku-band. The properties of these ferrites arise from exchange interactions between the oxygen and metallic ions occupying particular positions in its crystalline structure. For the substituted ferrite composites, the minimum RL shifts from in Ku-band to X-band when substituting Fe 3+ in hexaferrites by means of the variation of ferromagnetic resonance frequency which influences the microwave absorption properties.

The effect of polymerization temperature and reaction time on microwave absorption properties of Co-doped ZnNi ferrite/polyaniline composites

“…The value of tan δ μ for sample T-2 is greater than that of ZNCF in the range 2–12 GHz, which ascribes to the charge transfer between the ZNCF surface and PANI. 37 Sample T-2 exhibits best tan δ μ as compared with other composites. Besides, the comparison of all the samples indicates that sample T-2 exhibits similar tan δ μ and tan δ ε values, which can increase the degree of impedance matching and promote the EM wave absorption properties of materials.…”

Investigation of energy band-gap of the composite of hexaferrites and polyaniline

“…FTIR spectrum of PANI is given in Fig. 3e and its characteristic absorption peaks were found at around 804 cm −1 (out-of plane deformation vibration of benzene ring), 1123 and 1601 cm −1 (vibration band of N=Q=N) indicating the formation of PANI, 1297 cm −1 (N-H bending band of benzenoid rings) and 1486 cm −1 (C=N stretching of quinoid ring) [29][30][31][32][33][34]. Figure 3b-d shows FTIR spectra for HP1, HP2 and HP3 respectively.…”

Sintesis dan Karakterisasi Penyerapan Gelombang Mikro pada Komposit PANi - Barium Heksaferrit Tersubstitusi Mn dan Ti - CFO

“…Selain ukuran partikel, dilakukan rekayasa struktur kristal BHF yaitu substitusi Fe 3+ dengan kation lain atau kombinasi kation tetravalen (titanium, timah, zirconium, iridium, ruthenium) dan divalen (kobalt, magnesium, mangan, zink, nikel) yang umumnya digunakan untuk mengubah sifat fisika dan kimia heksaferrit tipe-M tergantung dari tujuan yang diinginkan (Ghzaiel: 2017). Pada penelitian ini, substitusi bertujuan untuk mengubah lebar serapan frekuensi dan meningkatkan serapan gelombang elektromagnetik.…”