scholarly journals Novel Polyimide/Copper-Nickel Ferrite Composites with Tunable Magnetic and Dielectric Properties

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1646
Author(s):  
Corneliu Hamciuc ◽  
Mihai Asandulesa ◽  
Elena Hamciuc ◽  
Tiberiu Roman ◽  
Marius Andrei Olariu ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Nickel Ferrite ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Broadband Dielectric Spectroscopy ◽  
Copper Nickel ◽  
Low Dielectric ◽  
Magnetic Remanence ◽  
Polyimide Matrix ◽  
Ferrite Composites

Heat-resistant magnetic polymer composites were prepared by incorporating cerium-doped copper-nickel ferrite particles, having the general formula Ni1-xCuxFe1.92Ce0.08O4 (x: 0.0, 0.3, 0.6, 1.0), into a polyimide matrix. The effects of particle type and concentration on the thermal, magnetic, and electrical properties of the resulting composites were investigated. The samples were characterized by FTIR, scanning electron microscopy, X-ray diffractometry, thermogravimetric analysis, differential scanning calorimetry, vibrating sample magnetometer, and broadband dielectric spectroscopy. The composites exhibited high thermal stability, having initial decomposition temperatures between 495 and 509 °C. Saturation magnetization (Ms), magnetic remanence (Mr), and coercivity (Hc) were found in range of 2.37–10.90 emu g−1, 0.45–2.84 emu g−1, and 32–244 Oe, respectively. The study of dielectric properties revealed dielectric constant values of 3.0–4.3 and low dielectric losses of 0.016–0.197 at room temperature and a frequency of 1 Hz.

Preparation of the copper-based polyoxometalate/polyurethane composites and their dielectric properties

2019 ◽  
Vol 28 (7) ◽  
pp. 473-483 ◽  
Author(s):  
İlhan Küçük ◽  
Sema Vural ◽  
Nilüfer Kıvılcım ◽  
İbrahim Adıgüzel ◽  
Süleyman Köytepe ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Metal Ion ◽  
In Situ Polymerization ◽  
Synthesis Method ◽  
Dielectric Constants ◽  
Morphological Properties ◽  
Polymerization Process ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Low Dielectric

The aim of this study is synthesis of polyurethane (PU) composites from 4,4′-methylenebis(cyclohexyl isocyanate), 1,2-ethanediol and different amounts of copper-based polyoxometalate (Cu-POM) and investigation of their dielectric properties. Firstly, Cu-POM structure as reinforcement was synthesized with ammonium heptamolybdate and Cu metal ion salt by a hydrothermal synthesis method. Then, Cu-POM-PU composites were prepared by in situ polymerization process. The prepared Cu-POM-PU composites were characterized by means of various techniques for their structure, morphology and thermal behaviour. The chemical structure, surface and morphological properties of the obtained composites were studied by Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) techniques. Thermal properties of these Cu-POM-PU composites were determined by thermogravimetric analysis, differential thermal analysis and differential scanning calorimetry analysis techniques. Dielectric properties of the Cu-POM-PU composites were also determined. The dielectric measured results showed that the dielectric constants decreased with the increase of the Cu-POMs content. The Cu-POM-PU composites showed relatively low dielectric constant compared to pure PUs.

scholarly journals Sintering, Microstructure, and Dielectric Properties of Copper Borates for High Frequency LTCC Applications

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4017
Author(s):  
Dorota Szwagierczak ◽  
Beata Synkiewicz-Musialska ◽  
Jan Kulawik ◽  
Norbert Pałka
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
High Frequency ◽  
Ceramic Materials ◽  
Sintering Behavior ◽  
Terahertz Time Domain Spectroscopy ◽  
Very High Frequency ◽  
X Ray ◽  
Low Dielectric ◽  
Very High

New ceramic materials based on two copper borates, CuB2O4 and Cu3B2O6, were prepared via solid state synthesis and sintering, and characterized as promising candidates for low dielectric permittivity substrates for very high frequency circuits. The sintering behavior, composition, microstructure, and dielectric properties of the ceramics were investigated using a heating microscope, X-ray diffractometry, scanning electron microscopy, energy dispersive spectroscopy, and terahertz time domain spectroscopy. The studies revealed a low dielectric permittivity of 5.1–6.7 and low dielectric loss in the frequency range 0.14–0.7 THz. The copper borate-based materials, owing to a low sintering temperature of 900–960 °C, are suitable for LTCC (low temperature cofired ceramics) applications.

scholarly journals Effect of TeO2 addition on the dielectric properties of CaCu3Ti4O12 ceramics derived from the oxalate precursor route

2013 ◽  
Vol 03 (04) ◽  
pp. 1350028 ◽  
Author(s):  
P. Thomas ◽  
K. B. R. Varma
Keyword(s):  
Dielectric Properties ◽  
Dielectric Loss ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Oxalate Precursor ◽  
X Ray ◽  
Practical Applications ◽  
Low Dielectric ◽  
Precursor Route ◽  
Tan Δ

CaCu 3 Ti 4 O 12 (CCTO) ceramics which has perovskite structure gained considerable attention due to its giant permittivity. But it has high tan δ (0.1 at 1 kHz) at room temperature, which needs to be minimized to the level of practical applications. Hence, TeO 2 which is a good glass former has been deliberately added to CCTO nanoceramic (derived from the oxalate precursor route) to explore the possibility of reducing the dielectric loss while maintaining the high permittivity. The structural, morphological and dielectric properties of the pure CCTO and TeO 2 added ceramics were studied using X-ray diffraction, Scanning Electron Microscope along with Energy Dispersive X-ray Analysis (EDX), spectroscopy and Impedance analyzer. For the 2.0 wt.% TeO 2 added ceramics, there is a remarkable difference in the microstructural features as compared to that of pure CCTO ceramics. This sample exhibited permittivity values as high as 7387 at 10 KHz and low dielectric loss value of 0.037 at 10 kHz, which can be exploited for the high frequency capacitors application.

Research on preparation and properties of graphene/copper nickel ferrite composites

2018 ◽  
Vol 47 (9) ◽  
pp. 921002
Author(s):  
马德跃 Ma Deyue ◽  
李晓霞 Li Xiaoxia ◽  
郭宇翔 Guo Yuxiang ◽  
曾宇润 Zeng Yurun
Keyword(s):  
Nickel Ferrite ◽  
Copper Nickel ◽  
Ferrite Composites

scholarly journals Magnetic Properties and Kinetic Roughening Study of Prepared Polyaniline- Lead Ferrite, Cobalt Ferrite and Nickel Ferrite Nanocomposites Electrodeposited Thin Films

2021 ◽  
Author(s):  
Leila Abbasi ◽  
Kambiz Hedayati ◽  
Davood Ghanbari
Keyword(s):  
Thin Films ◽  
Nickel Ferrite ◽  
Cobalt Ferrite ◽  
Thin Layers ◽  
X Ray ◽  
Force Microscopy ◽  
Kinetic Roughening ◽  
Composite Layers ◽  
Roughness Analysis ◽  
Ferrite Composites

Abstract The purpose of this study was to prepare polyaniline-lead ferrite, polyaniline-cobalt ferrite and polyaniline / nickel ferrite thin layers. The preparation process consists of two steps: First, ferrites are synthesized using a microwave irradiated hydrothermal method. The ferrites were then added separately to 0.1 M aniline electrolyte solution and 0.2 M sulfuric acid. The accumulation of polyaniline and ferrite composites was carried out in an electrochemical cell by electrodeposition method. The surface morphology of the composite layers was investigated by scanning electron microscopy and the percentage of the constituents was studied by X-ray energy scattering (EDX) analysis. Also, surface roughness analysis and kinetic roughening of thin films was performed using atomic force microscopy (AFM). Hysteresis loop of magnetic samples were investigated by vibrating sample magnetometer (VSM). The structure and crystalline size of samples studied by X-ray diffraction analyze.

scholarly journals Structure and dielectric properties of (1-x)Bi 0.5 Na 0.5 TiO 3–x BaTiO 3 piezoceramics prepared using hydrothermally synthesized powders

2021 ◽  
Vol 8 (7) ◽  
pp. 202365
Author(s):  
Andrea Nesterović ◽  
Jelena Vukmirović ◽  
Ivan Stijepović ◽  
Marija Milanović ◽  
Branimir Bajac ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Pyrochlore Phase ◽  
Processing Parameters ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
X Ray ◽  
Low Dielectric ◽  
Long Time ◽  
Time Periods

The influence of different processing parameters and various Ba 2+ addition (up to 10 mol%) on the structure and dielectric properties of Bi 0.5 Na 0.5 TiO 3 -BaTiO 3 (BNT-BT) ceramics was investigated. The powders were hydrothermally synthesized in the alkaline environment at 180°C for different time periods. X-ray diffraction confirmed the presence of dominant rhombohedral Bi 0.5 Na 0.5 TiO 3 phase and a small amount of secondary pyrochlore Bi 2 Ti 2 O 7 phase in the pure BNT powders. In addition, one-dimensional Na 2 Ti 2 O 7 structure was also observed in the powder hydrothermally treated for a long time (i.e. 48 h). The amount of secondary pyrochlore phase in the BNT-BT powders increases with the increase of Ba 2+ content. The synthesized powders were pressed into pellets and finally sintered at various temperatures up to 1150°C. High density (more than 90%TD) was obtained in all BNT-BT sintered samples. Optimal sintering parameters were chosen in order to obtain dense ceramics with the optimal phase composition. The temperature dependence of dielectric properties for the BNT-BT ceramics was also studied. Relaxor behaviour of BNT-based ceramics and broad transition peaks are evident in all samples. Dielectric constant up to 400 as well as an acceptable low dielectric loss at temperatures lower than 200°C were obtained in BNT-BT ceramics.

The Dependence of Dielectric Properties on Composition Variation in Ba0.6Sr0.4(YTa)yTi1-2yO3

2002 ◽  
Vol 720 ◽  
Author(s):  
Daniel Potrepka ◽  
Steven Tidrow ◽  
Arthur Tauber ◽  
Kevin Kirchner ◽  
Matthew Ervin ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Low Dielectric Constant ◽  
X Ray Diffraction ◽  
X Ray ◽  
Low Dielectric ◽  
Composition Variation ◽  
Device Applications ◽  
Improved Performance

AbstractBa0.6Sr0.4(YTa)yTi1-2yO3 has been shown to have properties which are promising for tunable applications requiring low dielectric constant [1]. Ba0.6Sr0.4(YTa)yTi1-2yO3 with y ≤ 0.10 has been synthesized and well-characterized using x-ray diffraction, EDAX, and Raman Spectroscopy. The dependence of the dielectric properties on concentration, y, of Y and Ta are discussed along with implications for improved performance in device applications.

The Influence of O2/Ar on the Dielectric Properties of Bismuth Zinc Niobate Titanium Thin Films Prepared by RF Magnetron Sputtering

2012 ◽  
Vol 252 ◽  
pp. 202-206
Author(s):  
Xiao Hua Sun ◽  
Zhi Meng Luo ◽  
Shuang Hou ◽  
Cai Hua Huang ◽  
Jun Zou
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Magnetron Sputtering ◽  
Photoelectron Spectroscopy ◽  
Rf Magnetron Sputtering ◽  
X Ray ◽  
Si Substrates ◽  
Low Dielectric ◽  
Metal Insulator Metal ◽  
Titanium Thin Films

BZNT (Bi1.5Zn0.5Nb0.5Ti1.5O7) thin films were prepared on Pt/Ti/SiO2/Si substrates by radio frequency (RF) magnetron sputtering in different O2/Ar ranging from 4:16 to 7:13. The structure and surface morphology of BZNT thin films were investigated by x-ray diffraction (XRD) and atom force microscopy (AFM). The analysis of component in BZNT films were carried out by x-ray photoelectron spectroscopy (XPS). The dielectric measurements were conducted on metal-insulator-metal capacitors at the frequency from 100 Hz to 1M Hz. It’s found that the O2/Ar ratios significantly influence the elements content in BZNT thin films and the morphology and dielectric properties of BZNT thin films. At 1M Hz, the dielectric constant of BZNT thin films deposited at O2/Ar ranging from 4:16 to 7:13 is 212, 187, 171, 196, respectively. The BZNT thin film prepared at O2/Ar = 6:14 shows the highest figure of merit for its very low dielectric loss of 0.0024.

Thermomechanical and dielectric properties of novel pyridine-based polyurethane urea elastomers

2017 ◽  
Vol 50 (3) ◽  
pp. 276-292 ◽  
Author(s):  
Stefan Oprea ◽  
Violeta Otilia Potolinca
Keyword(s):  
Dielectric Strength ◽  
Hexamethylene Diisocyanate ◽  
Scanning Calorimetry ◽  
Broadband Dielectric Spectroscopy ◽  
Low Dielectric ◽  
Segmental Relaxation ◽  
Static Mechanical ◽  
Amine Groups ◽  
Local Relaxation ◽  
Tetramethylene Oxide

In this article, novel pyridine-based polyurethane urea elastomers were synthesized from 1,6-hexamethylene diisocyanate and poly(tetramethylene oxide) glycol of molecular weight 1400 which was chain extended with 3,4-diaminopyridine. These new heterocyclic polyurethane urea elastomers were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and static mechanical measurements as a function of pyridine moieties content and the crosslinkers structure from the hard domains. This settlement of the amine groups on the pyridine rings realizes weak intermolecular hydrogen bonds compared with other pyridine derivatives studied by us. The molecular dynamics and local relaxation of these polyurethane urea elastomers were investigated using broadband dielectric spectroscopy. Results show that pyridine content slightly increases the glass transition temperature and has low dielectric strength of the segmental relaxation as a result of weaker cohesive domains.

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