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New three-phase composites, destined for application as dielectrics in the manufacturing of passive elements of flexible electronics, and based on polymer (PVDF) matrix filled with powdered ceramics of the hollandite-like (KFTO(H)) structure (5.0; 7.5; 15; 30 vol.%) and carbon (MWCNT) additive (0.5; 1.0; 1.5 wt.% regarding the KFTO(H) amount), were obtained and studied by XRD, FTIR and SEM methods. Chemical composition and stoichiometric formula of the ceramic material synthesized by the sol–gel method were confirmed with the XRF analysis data. The influence of the ceramic and carbon fillers on the electrical properties of the obtained composites was investigated using impedance spectroscopy. The optimal combination of permittivity and dielectric loss values at 1 kHz (77.6 and 0.104, respectively) was found for the compositions containing K1.6Fe1.6Ti6.4O16 (30 vol.%) and MWCNTs (1.0 wt.% regarding the amount of ceramic filler). [ABSTRACT FROM AUTHOR]

In this work, polymer matrix composites with the compositions PTFE/KFTO(H) and PTFE/KFTO(H)@CB and with filler volume fractions of 2.5, 5.0, 7.5, 15, and 30% (without and with carbon modification at a content of 2.5 wt.% regarding ceramic material) were produced by calendering and hot pressing and studied using FTIR, SEM, and impedance spectroscopy methods. Ceramic filler (KFTO(H)) was synthesized using the sol–gel Pechini method. Its structure was investigated and confirmed by the XRD method with following Rietveld refinement. The carbon black (CB) modification of KFTO(H) was carried out through the calcination of a mixture of ceramic and carbon materials in an argon atmosphere. Afterwards, composites producing all the components' structures weren't destroyed according to the FTIR results. The effect of carbon additive at a content of 2.5 wt.% relating to ceramic filler in the system of polymer matrix composites was shown, with permittivity increasing up to ε' = 28 with a simultaneous decrease in dielectric loss (tanδ < 0.1) at f = 103 Hz for composites of PTFE/KFTO(H)@CB (30 vol.%). [ABSTRACT FROM AUTHOR]

Polymethyl methacrylate/hollandite‐like copper doped potassium titanate high‐k ceramics composites with different filler content (20–60 vol.%) are prepared by simple method of mixing of the polymer solution and ceramics dispersion followed evaporation of the solvent and hot pressing. The particle morphology and size are estimated by SEM. The composites obtained are studied by XRD, FTIR, and TGA methods. The influence of the additive and the concentration of hollandite‐like copper doped potassium titanate high‐k ceramics on dielectric properties (permittivity, conductivity, dielectric loss tangent) are investigated at frequency range from 10−1 to 106 Hz. It is shown that the increasing of ceramics concentration cause the increasing of main dielectric characteristics, namely permittivity up to 40 and dielectric loss up to 0.13 at 60 vol.% of filler and 0.1 Hz. Conductivity percolation threshold for PMMA/KCTO(H) composites was estimated (vc = 0.0773 vol. [20.9 wt. %]). Experimental data on permittivity are compared with different theoretical models (Lichtenecker's model and the Effective Medium Theory model). [ABSTRACT FROM AUTHOR]

Polymer matrix composites based on ED-20 epoxy resin, hollandite K1.6(Ni0.8Ti7.2)O16 and carbon nanotubes with a variable content of 0.107; 0.213 and 0.425 vol.% were obtained for the first time. Initial components and composites produced were characterized by XRD, XRA, FTIR, SEM and Raman spectroscopy. The dielectric properties of composite materials were measured by impedance spectroscopy and determined by the volume ratio of the composite components, primarily by the concentration of CNTs. At a CNT content of 0.213 vol.% (before percolation threshold), the maximum synergistic effect of carbon and ceramic fillers on the dielectric properties of a composite based on the epoxy resin was found. Three-phase composites based on epoxy resin, with a maximum permittivity at a minimum dielectric loss tangent, are promising materials for elements of an electronic component base. [ABSTRACT FROM AUTHOR]

[Display omitted] • The thermal stability of the dielectric properties of the CCTO ceramic co-doped with La3+, Ni2+ and Sn4+ ions has been improved. • The effect of increasing the resistance of grain boundaries on improving the temperature stability of the dielectric loss tangent of Ca 1-x La 2x/3 Cu 3-y Ni y Ti 4-z Sn z O 12 ceramics has been studied. Dielectric properties control by elements co-doping is important research problem for application of ceramics based on CaCu 3 Ti 4 O 12 (CCTO) as a component of electronic devices. In this work, the effect of La3+, Ni2+ and Sn4+ co-doping on the dielectric properties of CCTO ceramics, including their thermal stability, was investigated. Solid solutions with compositions of Ca 1-x La 2x/3 Cu 2.95 Ni 0.05 Ti 3.7 Sn 0.3 O 12 (x = 0.010–0.055), Ca 0.94 La 0.027 Cu 3-y Ni y Ti 3.7 Sn 0.3 O 12 (y = 0.020–0.065), Ca 0.94 La 0.027 Cu 2.95 Ni 0.05 Ti 4-z Sn z O 12 (z = 0.25–0.4) were synthesized by the solid-state method at 970 °C. The incorporation of doping elements into the ceramic structure after sintering at 1080 °C was confirmed by X-ray diffraction data. Grain morphology and size of various solid solutions were estimated from scanning electron microscopy photographs. The optimal concentrations of doping elements were x = 0.04, y = 0.05, and z = 0.3, which is evident by high permittivity ε′ = 11,000 and low dielectric losses tanδ = 0.051 at f = 1 kHz. La3+, Ni2+ and Sn4+ co-doped CCTO ceramics demonstrated high stability of the permittivity in the temperature range from −60 to +125 °C. Based on the demonstrated dielectric properties, the presented solid solutions are suitable for use in ceramic capacitors. [ABSTRACT FROM AUTHOR]