In situ growth of B4C nanowires on activated carbon felt to improve microwave absorption performance

Abstract

Boron carbide (B4C) nanowires were synthesized on the surface of activated carbon felt (ACF) via an in situ thermal growth method. The microstructures of B4C nanowires were characterized by field emission scanning electron microscopy, transmission electron microscopy, and x-ray diffraction. The minimum reflection loss (RLmin) value of 40 wt. % ACF@B4C hybrid materials amounts to −36.1 dB at 17.2 GHz and the effective absorption bandwidth (RL < −10 dB) is obtained over a high frequency range of 15.9–18 GHz with an absorber layer thickness of 5 mm. The obtained results prove that ACF@B4C hybrid materials have high potential as microwave absorbers with excellent microwave absorption property.

Microstructure and microwave‐absorbing properties of B4C/C composite powders produced by combustion synthesis with an AC foaming agent

“…Among the existing dielectric loss ceramic materials, B 4 C exhibits remarkable potential as a P-type semiconductor with a relatively narrow energy band gap (2.09 eV), which brings a tunable conductivity and higher dielectric loss capacity owing to the easier electronic transition, and also with a low density (2.52 g/cm 3 ), a high hardness (29.1 GPa), and a high melting point (2450 • C) that lead to prominent thermostability, antioxidation, and noncorrosion. 9,10 To develop its microwave-absorbing properties, B 4 C/C composite powders are synthetized with novel morphologies comprising nuclear-shell, nanoparticle, nanowire, nanosheet, and porous structure in the recent studies, such as the B 4 C@GN nanosheets, which were prepared by a molten salt-mediated carbothermal reduction method 11 ; the ACF@B 4 C hybrid nanowires, which were prepared via an in situ thermal growth method 12 ; and the C-encapsulated B 4 C (B 4 C@C) nanoparticles, which were prepared via a sol-gel route. 13 Consequently, it is obvious that the higher conductivity, diverse composition, and various microstructures create more efficient microwave-absorbing properties owing to the improved conductive network and enhanced polarization.…”

Engineering multi-relaxation interfaces in Ti3C2T x for reducing wideband radar cross section

“…Material stealth technology can protect the aerodynamic performance of the weapon equipment as well as volume design [6]. The development of electromagnetic wave (EMW) absorbing materials with superior performance and radar cross section (RCS) reduction function is of profound significance to the vigorous progression of global information and military fields [7][8][9][10]. An ideal radar absorbing material must satisfy the two basic conditions.…”

Comparison of the microwave absorption performance of core–shell SiO2@C and hollow carbon nanospheres with different sizes

“…[1][2][3] According to previous research studies, it is essential for excellent absorbing materials to have the characteristics of strong absorption, low density and thin coating thicknesses in the widest possible frequency range. 1,[4][5][6][7][8][9] Therefore, different types of materials including magnetic materials, [10][11][12] dielectric materials, 6,[13][14][15] carbonaceous materials, [16][17][18] etc. have been explored, designed and applied to satisfy these demands in recent years.…”