Grain size effect in conductive phosphate / carbon nanotube ceramics

Plyushch, Artyom; Kuzhir, P.; Maksimenko, S. A.; Macutkevič, J.; Banys, J.; Sokal, Aliaksei; Lapko, Konstantin; Архипов, В. Е.; Окотруб, А. В.

doi:10.1016/j.ceramint.2016.12.151

Cited by 6 publications

(4 citation statements)

References 32 publications

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“…The temperature dependence of DC conductivity is presented in Figure 6 . Three different regions can be separated: (1) in 300–500 K temperature range the electrical conductivity increased with temperature due to the thermal activation mechanism [ 29 ], (2) below room temperature the electrical conductivity increased on cooling due to rapid shrinkage of ceramics, (3) and at very low temperatures (below 200 K) for ceramics with 50 wt.% Ag nanoparticles of 30–50 nm the electrical conductivity decreased on cooling due to the electron tunneling effects [ 30 ]. Above room temperature, the temperature dependence of DC conductivity fitted with the Arrhenius law:

where σ 0 is the pre-exponential factor, k is the Boltzmann constant and E is the activation energy.…”

Section: Resultsmentioning

confidence: 99%

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Phosphate Ceramics with Silver Nanoparticles for Electromagnetic Shielding Applications

Palaimienė

Macutkevič²,

Banys³

et al. 2022

Materials

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Ceramic composites with nanoparticles are intensively investigated due to their unique thermal, mechanic and electromagnetic properties. In this work, dielectric properties of phosphate ceramics with round silver nanoparticles of various sizes were studied in the wide frequency range of 20 Hz–40 GHz for microwave shielding applications. The percolation threshold in ceramics is close to 30 wt.% of Ag nanoparticles content and it is higher for bigger-sized nanoparticles. The microwave complex dielectric permittivity of ceramics above the percolation threshold is rather high (ε′ = 10 and ε″ = 10 at 30 GHz for ceramics with 50 wt.% inclusions of 30–50 nm size, it corresponds to almost 61% absorption of 2 mm-thickness plate) therefore these ceramics are suitable for microwave shielding applications. Moreover, the microwave absorption is bigger for ceramics with a larger concentration of fillers. In addition, it was demonstrated that the electrical transport in ceramics is thermally activated above room temperature and the potential barrier is almost independent of the concentration of nanoparticles. At very low temperature, the electrical transport in ceramics can be related to electron tunneling.

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where σ 0 is the pre-exponential factor, k is the Boltzmann constant and E is the activation energy.…”

Section: Resultsmentioning

confidence: 99%

“…The activation energy value was about several tenths of meV and it was almost independent of filler concentration. This is typical for thermally activated electrical conductivity [ 29 ].…”

Section: Resultsmentioning

confidence: 99%

Phosphate Ceramics with Silver Nanoparticles for Electromagnetic Shielding Applications

Palaimienė

Macutkevič²,

Banys³

et al. 2022

Materials

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“…MWCNT were synthesized via the chemical vapor deposition (CVD) method. Aligned MWCNT arrays were grown on silicon substrates as a result of the thermal decomposition of toluene at a temperature of 800 • C. The preparation method details can be found in [32], for example, and scanning and tunnelling electron microscopy of the nanotubes used have been presented in our previous works [27,33].…”

Section: Methodsmentioning

confidence: 99%

“…To understand the underlying physics the following idea may be proposed. It has been proven, that the conductivity of the MWCNT/ceramic composites has the tunnelling mechanism [33]. The tunnelling resistivity between two equivalent nanotubes can be calculated using the equation [37]:…”

Section: Radio Frequency Rangementioning

confidence: 99%

Synergy Effects in Electromagnetic Properties of Phosphate Ceramics with Silicon Carbide Whiskers and Carbon Nanotubes

et al. 2019

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Hybrid composite materials based on an aluminium phosphate matrix with silicon carbide whiskers and multi-walled carbon nanotubes were studied in a wide frequency range (20 Hz to 36 GHz). It was demonstrated, that the addition of the silicon carbide whiskers enhances the dielectric permittivity and conductivity. This was explained by the difference in tunnelling parameters. Hybrid ceramics with nanotubes and whiskers also exhibits substantially improved electromagnetic shielding properties. The hybrid ceramics with 10 wt. % silicon carbide whiskers and a 1 mm thick 1.5 wt. % carbon nanotube layer, show higher than 50% absorption of electromagnetic radiation.

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Rutile nanopowders for pigment production: Formation mechanism and particle size prediction

Zong-hua

Tang

2018

Chemical Physics Letters

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Grain size effect in conductive phosphate / carbon nanotube ceramics

Cited by 6 publications

References 32 publications

Phosphate Ceramics with Silver Nanoparticles for Electromagnetic Shielding Applications

Phosphate Ceramics with Silver Nanoparticles for Electromagnetic Shielding Applications

Synergy Effects in Electromagnetic Properties of Phosphate Ceramics with Silicon Carbide Whiskers and Carbon Nanotubes

Rutile nanopowders for pigment production: Formation mechanism and particle size prediction

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