Dielectric properties of BN modified carbon fibers by dip-coating

The effect of modifier contents of polyvinyl pyrrolidone on the enhanced dielectric and microwave absorbing properties of multiwalled carbon nanotubes

“…To investigate the intrinsic mechanism of microwave absorption of PVP/MWNTs hybrids, the complex relative permittivity of pristine MWNTs and PVP/MWNTs samples were measured in the frequency of 2–18 GHz, as shown in Figure . A few multi‐resonance peaks and leaping data points which appeared in the curves of complex permittivity, as shown in the imaginary part of permittivity in the range of 6–18 GHz, are a consequence of polarization relaxation effect . It can also be found that the ε′ and ε″ values of permittivity of pristine MWNTs decrease with increasing frequency, which is in the range of 23.9–18.1 and 10–4.2 over a frequency of 2–18 GHz.…”

“…A few multi-resonance peaks and leaping data points which appeared in the curves of complex permittivity, as shown in the imaginary part of permittivity in the range of 6-18 GHz, are a consequence of polarization relaxation effect. 21 It can also be found that the e 0 and e 00 values of permittivity of pristine MWNTs decrease with increasing frequency, which is in the range of 23.9-18.1 and 10-4.2 over a frequency of 2-18 GHz.…”

Preparation and characterization of silicon nitride (SiN)-coated carbon fibers and their effects on thermal properties in composites

“…Among the various types of inorganic particles used as hybrid heat-conducting fillers, such as silicon carbide (SiC) [27], aluminum nitride (AlN) [16,28,29], and boron nitride (BN) [30,31], silicon nitride (Si N) [32][33][34][35] has been used in a wide range of applications. This is because of its many beneficial inherent properties, including its low density, low thermal expansion coefficient, hightemperature strength, high rigidity, and superior heat resistance.…”

Preparation of Boron Nitride-Coated Carbon Fibers and Synergistic Improvement of Thermal Conductivity in Their Polypropylene-Matrix Composites

“…Decoration of CF with ceramic films and/or particles is one of the ways used to form a superior thermally conductive CF-based composite with an electrically buffering coating [17]. There are a variety of methods to fabricate ceramic coatings, including sintering [18,19], laser cladding [20], dip-coating [21][22][23], chemical vapor deposition (CVD) [24][25][26][27], magnetron sputtering [28,29], or a sequence of all or some of these processes. Although sintering and CVD are considered to be the primary methods for the large-scale fabrication of ceramic-coated fibers, they impose several restrictions, including high cost, complexity, and difficulty of operation, as well as enormous energy consumption.…”

“…They analyzed the effect of various compositions (via molarity control) of boriding solution and nitriding temperature (up to 1000 • C) on the morphology of ceramic coatings [21]. Following a similar dip-coating process of BN on CF substrates, Zhou et al studied the effect of BN coatings on the dielectric properties of paraffin-matrix composites reinforced with treated CFs [23]. Here, we report the preparation and characterization of BN-CFs using only a gaseous source of nitrogen in a high-temperature (1400 • C) furnace.…”