Dielectric behaviour of CaCu3Ti4O12-epoxy composites (original) (raw)

Dielectric Properties of Epoxy / BaTiO 3 Composites

2010

Dielectric properties such as relative permittivity (dielectric constant) (ε′) and dielectric loss (ε") of (epoxy resin-barium titanate) composites behaviour as a function of barium titanate volume fractions (5, 10, 15, 20, 25, 30, 35, 40) vol.%, temperature in the range (30-110) • C and frequency in the range (120Hz-2MHz), were investigated and given a qualitative explanation. The permittivity was found to increase with the increase of BaTiO 3 filler content, and was high in the low frequency range, but diminishes as the frequency increases. The permittivity was found to increase with the increase of temperature up to the transition temperature (Tg). Ac. conductivity and impedance of the composites behaviours as function of frequency and temperature have also been investigated. [

Dielectric Constant of nano-CCTO / Epoxy Composite

Nanocrystalline multiphase CaCu 3 Ti 4 O 12 (CCTO) was prepared using Ca(NO 3 ) 2 .4H 2 O, Cu(NO 3 ) 2 .3H 2 O, TiO 2 and C 2 H 2 O 4 .2H 2 O. The X-Ray differection and SEM analysed of the prepared CCTO powder sintered at 900 o C and 950 o C.

Dielectric properties of CaCu3Ti4O12–silicone resin composites

Applied Physics A, 2012

CaCu 3 Ti 4 O 12 (CCTO)-silicone resin composites with various CCTO volume fractions were prepared. Relatively high dielectric constant (ε = 119) and low loss (tan δ = 0.35) of the composites with CCTO volume fraction of 0.9 were observed. Two theoretical models were employed to predict the dielectric constant of these composites; the dielectric constant obtained via the Maxwell-Garnett model was in close agreement with the experimental data. The dielectric constant of CCTO-silicone resin composites showed a weak frequency dependence at the measuring frequency range and the loss tangent apparently decreases with increase in frequency.

Modelling and dielectric behavior of ternary composites of epoxy (BaTiO3/CaTiO3)

The European Physical Journal Applied Physics, 2007

The aim of this article is to explore materials made of polymer-titanate composites for application towards the size reduction of high frequency electronic components. A study has therefore been done on the dielectric effect of composites made of an epoxy matrix loaded with a mixture of barium titanate and calcium titanate. The effects have been quantified according to volume fraction of load. Results obtained from time domain reflectometry have been compared to modelling predictions from the generalized Lichtenecker law. Low frequency analysis (in the range DC-500 MHz) has also been performed throughout this work, and it has primarily concentrated on conductivity behaviour which may be attributed to the effects of a percolation process. The study has confirmed the validity of the ternary mixture law being applied in order to predict the electromagnetic behaviour of the composite material. This material family may therefore find use in microelectronic applications and in the miniaturization of circuit components (substrates, components, cavities, antennas, etc.). PACS. 77.84.Lf Composite materials-78.47.+p Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter-77.84.Dy Niobates, titanates, tantalates, PZT ceramics, etc.

Dielectric Constant of nano- CCTO / Epoxy Composit

Dielectric Properties of Filled Composites of Epoxy Resin

Journal of Basic & Applied Sciences, 2014

The addition of fillers in composite of epoxies, improves the dielectric response of the epoxies. The dielectric properties of unfilled and filled composites of epoxy resins have been studied as a function of thickness in the frequency range 10-1 Hz to 10 5 Hz at room temperature. The response of the unfilled samples shows that the composites behave as an insulator for all thickness. In filled composites at small thickness (0.32 mm) the response shows a loss peak in low frequency regime. The peak is broader than the Debye loss peak which is obscured by the dc conductance. At frequencies greater than p the response shows a well defined power law behaviour after the subtraction of C. Similar behaviour has been observed at different thickness.

Dielectric properties ofPoly(methyl methacrylate) (PMMA)/CaCu3Ti4012 Composites

Materials with high dielectric constant are in great demand for the miniaturization of electronic devices. More specifically, high dielectric constant polymer-ceramic composites are useful for embedded capacitor applications. A composite consisting of giant dielectric CaCu3 Ti4012 (CCTO) incorporated into the Poly(methyl methacrylate) (PMMA) polymer matrix has been fabricated by melt mixing followed by hot pressing. The composites thus fabricated has been characterised for structural, morphological and dielectric properties. The effective dielectric constant of the composite increased when the CCTO content increased in the PMMA matrix. The dielectric constant permittivity of PMMA is around 4.9 @ 100Hz which has increased to 15.7 @ 100Hz when the ceramic content has increased to 40 Vol %. At low frequency, space charge polarisation is dominant. This composite also exhibited remarkably low dielectric loss at high frequency, which makes this composite a suitable candidate for the capacitors in high frequency application.

Dielectric behavior of a sintered heterogeneous ternary composite resin/BT/Cu2O

The European Physical Journal Applied Physics, 2017

In this paper, we investigate and model the dielectric behavior of a ternary composite prepared at room temperature with a mixture of epoxy resin (RE), barium titanate (BT) and copper oxide (Cu 2 O), sintered at three different temperatures (150°C, 200°C, and 250°C). Time domain spectroscopy (TDS) is used to characterize samples in the range [DC to 2 GHz] by performing a particular study at low frequency (500 MHz). The latter focused on both the sintering and the Cu 2 O addition effects on a ternary composite dielectric behavior. These effects were quantified as a function of the BT volume fraction. For this purpose, we used an optimization method based on nonlinear regressions to determine the permittivity, to minimize systematic errors of this dielectric parameter, and to show the effect of Cu 2 O on it. Moreover, we attempt to explain the sintering temperature effect on this kind of mixtures through the modified Lichtenecker model. As a matter of fact, the importance of this law is allocated on one hand to the validation and concordance of the experimental results with those of the theory and on the other hand to the temperature effect investigation on the form factor given by the modified Lichtenecker law.

Dielectric characterisation of epoxy nanocomposite with barium titanate fillers

IET Nanodielectrics, 2020

High permittivity materials are currently in use for mitigation of electrical stress in high-voltage apparatus and energy storage systems. In this work, epoxy-based high permittivity nanocomposites with Barium titanate (BaTiO 3) nanofillers are considered, for the purpose of stress mitigation. Uniform dispersion of the fillers in the polymer up to 10% by volume is achieved. Apart from the use of as-received fillers, the effect of using surface-functionalised nanoparticles (with 3glycidoxypropyltrimethoxy-silane) before use is also investigated. The nanocomposite is characterised in terms of its complex permittivity, DC conductivity, short-term AC breakdown strength and space charge accumulation, to gauge its suitability for use in high-voltage insulation. Complex permittivity is measured using broadband dielectric spectroscopy over a broad frequency range of 1 mHz to 1 MHz. DC conductivity is studied from polarisation-depolarisation current measurements. Short-term AC breakdown strength tests are performed at power frequency (50 Hz). Space charge density along the sample thickness is obtained using pulsed electro-acoustic technique. A computational case-study is presented to show the feasibility of using the high permittivity nanocomposite for electric stress control in high-voltage equipment (viz., at mounting flanges of 69 kV bushings).

Computational Approach of Dielectric Permitivities in BaTiO3--Epoxy Composites

Journal of Composite Materials, 2008

A numerical approach using a finite element method (FEM) was performed in order to determine the dielectric constant (ε') of BaTiO 3—epoxy composites. In order to diminish computational resources and analyse simple models, composite topology was represented by periodic structures based on FCC configurations, but introducing novel packaging protocols, defining the way composites are filled as particle concentration is increased. The dielectric response of these anisotropic and periodic structures was mathematically represented through a quasi-static approximation using the Laplace equation. The amount of inclusions was varied in order to represent diluted and concentrated systems and structures were assessed for the whole feasible range of volume fractions. The numerical results were compared with experimental data concluding that only packaging protocols that consider higher particle—particle interaction are suitable to represent the dielectric behavior of concentrated-composite...

Dielectric behaviour of CaCu3Ti4O12-epoxy composites (original) (raw)

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