Preparation of SiO2 Matrix Composite with Tunable Dielectric Properties in Radio Frequency Range

2016 ◽  
Vol 848 ◽  
pp. 364-368
Author(s):  
Zi Dong Zhang ◽  
Chen Qin ◽  
Xiu Jie Ji ◽  
Hui Min Wang ◽  
Shu Hui Chen ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Radio Frequency ◽  
Self Assembly ◽  
Xrd Analysis ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Impedance Analyzer ◽  
X Ray ◽  
The Matrix ◽  
Periodical Structure

In this paper, C/SiO2 composites were fabricated by self-assembly process combined with heat treatment. The X-ray diffraction (XRD) analysis, SEM and impedance analyzer were used to investigate the microstructure and radio-frequency dielectric properties of the composites. The results showed that the matrix of C/SiO2 composite with a periodical structure formed by the hexagonal stacking of SiO2 microspheres. The sheet carbon distributes in pores formed by SiO2 microspheres and act as the functional phase in the composite. The results indicate that the permittivity of C/SiO2 composite could be easily adjusted by controlling the content of Carbon in the composite. Both real and imaginary parts of the permittivity increase with the content of carbon, but decrease with the frequency.

Dielectric Properties and Raman Spectroscopy in Ca-Substituted Na0.5Bi0.5TiO3 Ferroelectric Ceramics

2011 ◽  
Vol 324 ◽  
pp. 298-301 ◽  
Author(s):  
Roy Jean Roukos ◽  
Olivier Bidault ◽  
Julien Pansiot ◽  
Ludivine Minier ◽  
Lucien Saviot
Keyword(s):  
Raman Spectroscopy ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Rhombohedral Phase ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Ferroelectric Ceramics ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
X Ray

Lead free Na0.5Bi0.5TiO3 (NBT) and (Na0.5Bi0.5TiO3)1-x(CaTiO3)x (NBT-CT) piezoelectric ceramics with the perovskite structure were studied. The NBT and NBT-CT samples were synthesized using a solid-state reaction method and characterized with X-ray diffraction (XRD), Raman spectroscopy and dielectric measurements for several compositions (x = 0, 0.07, 0.15) at room temperature. The XRD analysis showed a stabilization of a rhombohedral phase at a low concentration of Ca (0 < x <0.15), whereas Raman spectra reveal a strong modification for the sample with x = 0.15. The dielectric properties of these ceramics were studied by measuring impedance in the 79-451K temperature range for unpoled and field cooling with an electric field (FC) conditions.

scholarly journals Variasi Jarak Antar Layer Bentonit Pada Pembuatan Nanokomposit Pla-Bentonit Sebagai Kemasan Makanan

2020 ◽  
Vol 8 (1) ◽  
pp. 57-65
Author(s):  
Vita Wonoputri ◽  
Natasha Emanuella ◽  
Evelyn Angelica ◽  
Johnner Sitompul
Keyword(s):  
Food Packaging ◽  
Water Vapor Permeability ◽  
Xrd Analysis ◽  
Basal Spacing ◽  
Vapor Permeability ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Matrix ◽  
Treatment Data ◽  
Octadecyl Amine

In this study, bentonite was used as a filler in the synthesis of polylactic acid (PLA) nanocomposite. The mechanical property of PLA-Bentonite nanocomposite was treated using two different surfactants, namely octadecyl amine (ODA) and trimethyl stearyl ammonium chloride (TSC) at two different concentration (20 mmol and 40 mmol). The treatments of ODA and TSC in the matrix with regards to the basal spacing of bentonite stacks  measured by X-Ray Diffraction (XRD) analysis. The results showed a significant increase in basal spacing was obtained when TSC 40 was applied for treatment. Data of Fourier Transform Infrared Spectroscopy (FTIR) suggested that this increase was caused by the incorporation of surfactant into the bentonite stacks. Most of the PLA-Bentonite nanocomposite can form intercalation structure, while a sample containing TSC 40 formed exfoliation structure. This exfoliation structure resulted in a film with the best tensile strength and water vapor permeability compared to the others. The film containing TSC 40 showed the lowest reduction in water activity, almost similar to the bread sample wrapped using conventional plastic. The bread wrapped with TSC 40 film was not grown by fungi as opposed to the conventional plastic, showing the potential of the nanocomposite film as food packaging.

STUDY OF HYDROTHERMAL SYNTHESIS AND PROPERTIES OF Bi2Fe4O9

2010 ◽  
Vol 03 (03) ◽  
pp. 173-176 ◽  
Author(s):  
YIBO WANG ◽  
HUAJUN SUN ◽  
JING ZHOU ◽  
BO LI ◽  
CHENGYONG ZHANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Transformation ◽  
Dielectric Properties ◽  
X Ray Diffraction ◽  
Impedance Analyzer ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Highly oriented Bi2Fe4O9 nanosheets can be fabricated with Fe(NO3)3 ⋅ 9H2O and Bi(NO3)3 ⋅ 5H2O using the low-temperature hydrothermal method. The as-prepared powders are characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM), which exhibit an excellent orientation along the (00l) planes. The leakage current density and dielectric properties of the nanosheet samples are measured by Radiant Precision Workstation and HP4291B Impedance Analyzer, respectively. The effects of NaOH concentration on the phase transformation, sheet size and morphologies of the Bi2Fe4O9 crystallites are studied in this paper.

Structural and Dielectric Properties of Na0.5Bi0.5TiO3 Ferroelectric Ceramics

2012 ◽  
Vol 585 ◽  
pp. 219-223
Author(s):  
Rekha Kumari ◽  
N. Ahlawat ◽  
Ashish Agarwal ◽  
M. Sindhu ◽  
N.N. Ahlawat
Keyword(s):  
Dielectric Properties ◽  
Solid State Reaction Method ◽  
Wide Frequency Range ◽  
Ferroelectric Ceramics ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
X Ray ◽  
Different Temperatures

Na0.5Bi0.5TiO3 (NBT) ceramics were synthesized by conventional solid state reaction method. Structural and dielectric properties of these ceramics were investigated. Crystalline phase of sintered ceramics was investigated by X-ray diffraction (XRD). The Rietveld refinement of powder X-ray diffraction revealed that the prepared ceramics exhibit the rhombohedral space group R3c. Dielectric properties of Na0.5Bi0. analyzer.5TiO3 (NBT) ceramics were studied at different temperatures in a wide frequency range using impedance

scholarly journals Effect of Transition Metal on Structural and Dielectric Properties of Mg0.5Tm0.5Fe2O4 (Tm = Zn and Cu) System

2021 ◽  
Author(s):  
Pallavi Saxena ◽  
Anand Yadav
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Interfacial Polarization ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
High Frequencies ◽  
X Ray ◽  
Cubic Structure ◽  
High Dielectric

This study explored the structural and dielectric features of Mg0.5Tm0.5Fe2O4 (Tm = Zn and Cu) that were synthesized by the Solid-state reaction (SSR) method. The X-ray powder diffraction (XRD) analysis reveals that the prepared samples are single-phase cubic structure without any impurity. Rietveld-refined X-ray diffraction results reveal the formation of cubic structure and all the peaks of Mg0.5Zn0.5Fe2O4 and Mg0.5Cu0.5Fe2O4 are perfectly indexed in the cubic (Fd-3 m) structure. Dielectric constant and dielectric loss variation with frequency were also explored. Both decrease when the relevant alternating field is increasing and become constant at high frequencies which reflects the important role of interfacial polarization. Furthermore, the Mg0.5Cu0.5Fe2O4 having the smallest crystallite size (~ 44.73 nm) has a high dielectric constant (~ 4.41 × 104) value as compare to Mg0.5Zn0.5Fe2O4.

scholarly journals Study of structural and dielectric properties of Nickel-doped BaTiO3 material

2019 ◽  
Vol 8 (3) ◽  
pp. 228-233
Author(s):  
Hafes Ed-Dnoub ◽  
Ouafae El Ghadraoui ◽  
Mohammed Zouhairi ◽  
Ahmed Harrach ◽  
Tajeddine Lamcharfi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Electron Microscope ◽  
Transition Temperature ◽  
Dielectric Properties ◽  
Scanning Electron Microscope ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
X Ray ◽  
Perovskite Type ◽  
Scanning Electron

In this work, the effect of nickel (Ni) insertion on the structural and dielectric properties of BaTiO3 material was investigated. A series of powders of composition Ba1-xNixTiO3 (x = 0, 0.05, 0.1, 0.15 and 0.20) were synthesized by solid method. The analysis by X-Ray Diffraction (XRD) shows that the obtained compounds crystallize in a phase of perovskite type. All the peaks are indexed in a phase of quadratic symmetry. Characterization by the Scanning Electron Microscope (SEM) indicates a heterogeneous microstructure of the grains. The study by spectroscopy of impedance in the frequency range [500Hz-1MHz] highlighted the effect of the nickel insertion on the transition temperature and the dielectric constant value.

Effect of the Addition of Nano-β-TCP on the Microstructure of Mg-Zn-Zr Alloy

2012 ◽  
Vol 535-537 ◽  
pp. 259-263 ◽  
Author(s):  
Chen You ◽  
Yan Ze Bi ◽  
Min Fang Chen ◽  
Yue Sun ◽  
De Bao Liu
Keyword(s):  
Xrd Analysis ◽  
Potential Interaction ◽  
Spherical Particles ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Matrix ◽  
Diffraction Peaks ◽  
Zr Alloy

In this study, a mental matrix composite (MMC) made of Mg-3Zn-0.8Zr alloy as a matrix and β-TCP particles as reinforcements were prepared for investigating the effect of β-TCP spherical particles sized in 100 nm on the microstructure of that alloy. The grains of as-cast or as-extruded Mg alloys systematically decreased from about 80 μm to about 30 μm with the choice of β-TCP contents. X-ray diffraction (XRD) analysis and optical microscopy (OM) observations show that the Mg-3Zn-0.8Zr-β-TCP (1.0 or 1.5, in wt %) composites were composed of various phases in addition to Mg and MgZn2 comparied with Mg-Zn-Zr alloy. New diffraction peaks appearing in the MMC, which suggests that a potential interaction occurred between β-TCP and the matrix. Transmission electron microscopy (TEM) images reveal that secondary phases, which wraps upon the surface of β-TCP, are uniformly distributed in the grains of Mg-Zn-Zr alloy. Energy spectrum analysis shows that the component of dark-colored parts is equivalent to β-TCP, but the component of light-colored parts is Mg-Zn-Ca, which demonstrates that there is a real interaction occurred between the matrix and β-TCP.

scholarly journals Effect of Zinc Doping on the Electrical and Dielectric Properties of CCTO Compound Synthesized by Solid-State Method

2021 ◽  
Vol 33 (9) ◽  
pp. 2000-2006
Author(s):  
M. Slaoui ◽  
N. Gouitaa ◽  
Y. El Issmaeli ◽  
A. Harrach ◽  
F. Abdi ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Solid State ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
X Ray ◽  
Zn Concentration ◽  
Zinc Doping ◽  
Electrical And Dielectric Properties

In this work, the influence of zinc doping on structural and dielectric properties of CaCu(3-x)ZnxTi4O12 (CCZxTO with x = 0, 2.5, 5, 7.5, 10, 12.5 and 15%) ceramics sintered at 1000 ºC for 8 h was studied. The ceramic samples were prepared by the conventional solid-state and calcined at 1050 ºC for 4 h. The X-ray diffraction (XRD) analysis of pure and Zn-doped CCTO were analyzed by using Rietveld refinement with cubic CCTO phase with no trace impurity phase. The scanning electron microscopy (SEM) investigation showed that for Zn-doped CCTO, the grains distributions were homogenous with average sizes which decreased with increasing of Zn concentration. The dielectric permittivity as function of temperature showed two dielectric anomalies (weakly and strong) and the dielectric constant value largely decreased for x = 2.5%, which is about tree magnitude smaller than the pure ceramic. Then it increased and reached a maximum at x = 10%, which is larger than the value of pure ceramic. And for x > 10%, the dielectric constant decreased for about two magnitude smaller than the ceramic at x = 10%. The cole-cole diagramm for all the samples showed existence of two semi-arcs attributed to the grains and grains boundaries. It was found that the Rg values were much smaller than the Rgb value. This give an evidance on the formation of interior barrier layer capacity (IBLC).

Preparation and Structural Characterization of CaCu3Ti4O12 Doped with Nickel, Ferrite, Manganese and Cobalt

2014 ◽  
Vol 893 ◽  
pp. 69-74
Author(s):  
Johar Banjuraizah ◽  
Mohd. Haziq Che Ani ◽  
A.R. Mohamed
Keyword(s):  
Dielectric Properties ◽  
Room Temperature ◽  
Synthesis Method ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Value ◽  
Small Grains ◽  
Dielectrical Properties

Transition metal oxide-doped CCTO (CaCu3Ti4O12) ceramics were prepared by a conventional solgel synthesis method and the effects of pure CCTO and CCTO doped with Mn, Fe, Co, Ni to the crystal structure, microstructures and dielectrical properties of samples were investigated. The phase composition and microstructure were studied by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD analysis reveals that all samples exhibited multiphases with the pseudo-perovskite cubic CCTO phase with space group Im-3 as the main phase in undoped and doped CCTO samples. Peaks of monoclinic CuO and peroveskite CaTiO3 could also be seen in all samples which indicate that solid solution of CuO in CaTiO3 lattice was incomplete.SEM results show that doping effectively enhanced densification. SEM micrographs also suggested that the morphologies of doped CCTO ceramics had showed a matrix consisting of large grains wherein the small grains were embedded between the larger grains. Dielectric properties of pure and doped CCTO were investigated in a broad frequency range of the dielectric constant reached a value as high as εr = 29.4 at room temperature for CCTO doped with Ni at frequency (1000 Hz). Besides the sintering conditions, the microstructure and the dielectric properties of the CCTO are strongly influenced by type of doping elements.

Dielectric Properties of Zr-Doped CCTO Based Ceramics Prepared via Sol-Gel Method

2012 ◽  
Vol 528 ◽  
pp. 121-125 ◽  
Author(s):  
Chao Qun Ye ◽  
Li Ding
Keyword(s):  
Dielectric Properties ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Impedance Analyzer ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Microstructure Morphology ◽  
Comprehensive Characterization ◽  
Scanning Electron

The CaCu3Ti4O12 and Zr-doped polycrystalline CaCu3Zr0.05Ti3.95O12 were prepared via sol-gel method. Comprehensive characterization including X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) equipped with Energy-dispersive X-ray spectroscopy (EDX) were employed to characterize the microstructure, morphology and composition. The dielectric properties of the CCTO based ceramics were studied using impedance analyzer. The results show that replacement of Zr in the Ti- site can achieve the effect of regulation of the dielectric properties.

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