Silicon carbide/phosphate ceramics composite for electromagnetic shielding applications: Whiskers vs particles

Plyushch, Artyom; Macutkevič, J.; Svirskas, Šarūnas; Banys, J.; Plaušinaitienė, Valentina; Bychanok, D.; Maksimenko, S. A.; Selskis, Algirdas; Sokal, Aliaksei; Lapko, Konstantin; Kuzhir, P.

doi:10.1063/1.5093421

Cited by 23 publications

(17 citation statements)

References 32 publications

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“…Although the polymer-metal composites alleviate the problems associated with corrosion and oxidation, they suffer from heavy weight and degraded efficiency at elevated temperatures. [31,32] Ceramics, [33][34][35][36][37][38][39][40] carbon fibers, [41][42][43][44][45][46][47][48] carbon black, [49,50] carbon nanotubes, [51][52][53][54][55][56][57] graphite, [58][59][60] reduced graphene oxide, [5,8,[61][62][63][64][65][66][67][68][69][70][71] graphene, [72][73][74][75][76] ferromagnetic materials, [77][78]…”

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confidence: 99%

Multifunctional Graphene Composites for Electromagnetic Shielding and Thermal Management at Elevated Temperatures

Barani

Kargar

Mohammadzadeh

et al. 2020

Adv Elect Materials

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EM radiation. For this reason, the electronic components have to be protected from the intra-and inter-system EM radiations in order to avoid fast degradation and failure. [4-14] It has also been suggested that prolonged exposure to even nonionizing EM waves in the MHz and GHz frequency range may have detrimental effects on humans and other living beings making the EMI shielding important from safety perspectives. [15-19] The dense packing of the electronic components in the state-of-the-art 2D, 2.5D, and 3D integrated systems and generation of high heat fluxes create an environment with high temperatures, which adversely affect the efficiency and stability of the EMI shielding materials. [20,21] The absorption of EM waves results in the temperature rise of the material making the situation even worse. The data on the efficiency of the conventional and recent EM shield materials in most cases are limited to room temperature (RT) operation. [20-23] The latter is despite the fact that many new non-metallic materials, introduced for EMI shielding, suffer from thermal instability, oxidation, or significant reduction in the shielding efficiency at high temperatures. These concerns require development of novel multifunctional materials, which can serve concurrently as an excellent EM shields with the high thermal stability and conductivity at elevated temperatures. The ability of such materials to act as the thermal interface materials (TIMs) which can dissipate heat efficiently becomes a necessity rather than an extra bonus feature. [2,3,20,21,24] TIMs are applied between two solid surfaces in order to fill the microscopic voids at the interface, and enhance the thermal transport from a heat source to a heat sink. [25-27] The base materials for TIMs are amorphous polymers, which have low thermal conductivity, typically in the range from 0.2 to 0.5 Wm −1 K −1. [28] For this reason, the polymers used as base materials for TIMs are filled with highly thermally conductive fillers to enhance their overall thermal conductivity. The lowweight, mechanical stability, resistance to oxidation, flexibility, and ease of manufacturing are other important criteria for TIMs. EMI shielding materials block the incident EM waves by reflection and absorption mechanisms. Both mechanisms

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confidence: 99%

Multifunctional Graphene Composites for Electromagnetic Shielding and Thermal Management at Elevated Temperatures

Barani

Kargar

Mohammadzadeh

et al. 2020

Adv Elect Materials

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“…The calculations of electromagnetic shielding of thin composite plate embedded in waveguide according to equations presented in ref. [33] (please see Table 2) indicate that composites, depending from AgNPs size and concentration, are suitable for electromagnetic shielding applications. [34] T A B L E 1 Percolation threshold, fc, and corresponding critical exponents of the permittivity, g, and of the electrical conductivity, t, below and above the threshold Below room temperature, the electrical conductivity increases when the temperature decreases, and reaches a maximum around 180 K, which is close to the glass transition temperature of the pure PDMS matrix (150 K) ( Figure 4).…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Electrical percolation and electromagnetic properties of polydimethylsiloxane composites filled with Ag nanoparticles of different sizes

et al. 2020

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This paper deals with the electrical properties of polydimethylsiloxane nanocomposites filled with Ag nanoparticles (AgNPs) of different sizes. The measurements were carried out over a very broad range of frequencies (20 Hz‐40 GHz), and the results showed that the percolation threshold in the composites is close to 20 vol% and that it is almost independent of particle size. The observed critical exponents reasonably agree with the theoretical values. Above the percolation threshold, the values of dielectric permittivity and electrical conductivity are quite high, ε′ ≈ 107 and σ ≈ 1 S/cm at room temperature and frequency of 129 Hz (which is close to our low frequency limit). The dielectric permittivity of composites decreases strongly with frequency, especially in the microwave range, while the frequency behavior of conductivity strongly depends on the concentration of nanoparticles. Nevertheless, the electrical conductivity and the dielectric permittivity remain high at microwaves (0.1 S/m and 10, respectively), for composites with AgNPs of size 80 to 100 nm at a concentration of 30 vol%.

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“…The results are presented in Figure 4, based on calculations using the equations presented in ref. [31]. It can be concluded that layers of carbon gel with a thickness of 2 or 4 mm and a low density of about 0.2 g/cm 3 presented an absorption close to 0.5.…”

Section: Porosity Of Carbon Gelsmentioning

confidence: 88%

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Electromagnetic Properties of Carbon Gels

et al. 2019

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The electromagnetic properties of various carbon gels, produced with different bulk densities, were investigated in a wide frequency range (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36). The values of dielectric permittivity and electrical conductivity at 129 Hz were found to be very high, i.e., more than 10 5 and close to 100 S/m, respectively. Both strongly decreased with frequency but remained high in the microwave frequency range (close to 10 and about 0.1 S/m, respectively, at 30 GHz). Moreover, the dielectric permittivity and the electrical conductivity strongly increased with the bulk density of the materials, according to power laws at low frequency. However, the maximum of microwave absorption was observed at lower densities. The DC conductivity slightly decreased on cooling, according to the Arrhenius law. The lower activation energies are typical of carbon gels presenting lower DC electrical conductivities, due to a higher number of defects. High and thermally stable electromagnetic properties of carbon gels, together with other unique properties of these materials, such as lightness and chemical inertness, open possibilities for producing new electromagnetic coatings.

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Silicon carbide/phosphate ceramics composite for electromagnetic shielding applications: Whiskers vs particles

Cited by 23 publications

References 32 publications

Multifunctional Graphene Composites for Electromagnetic Shielding and Thermal Management at Elevated Temperatures

Multifunctional Graphene Composites for Electromagnetic Shielding and Thermal Management at Elevated Temperatures

Electrical percolation and electromagnetic properties of polydimethylsiloxane composites filled with Ag nanoparticles of different sizes

Electromagnetic Properties of Carbon Gels

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