scholarly journals Effect of ZrO2 Doping on the Microstructure and Dielectric Properties of Ca0.97Y0.03Cu3Ti4-xZrxO12 Ceramics

2021 ◽  
Author(s):  
Haibo YU ◽  
Yanliang WEI ◽  
Xiaolin ZHANG ◽  
Dang WANG ◽  
Yuying ZHANG ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Grain Boundaries ◽  
Single Phase ◽  
Reaction Sintering ◽  
Doping Amount ◽  
Sem Images ◽  
Grain Sizes ◽  
Ceramic Samples ◽  
All Ceramic ◽  
Sintering Method

Abstract Dielectric properties of CaCu3Ti4O12 (CCTO) ceramics were studied by doping amount of Zr4+ donor on the basis of doping Y3+ donor. Ca0.97Y0.03Cu3Ti4-xZrxO12 (x=0, 0.005, 0.010, 0.015, CYCTZO) ceramics were prepared by reaction sintering method, and the phase structure, microstructure and dielectric properties of the ceramics were studied. The single phase CCTO was detected in all ceramic samples. SEM images of samples showed a high density and uniform-sized microstructure, and the average grain sizes of the ceramics was reduced with increasing content of Zr4+ donor. Interestingly, the dielectric constant (εr) was increased significantly while the dielectric loss tangent (tanδ) was decreased with the suitable doping amount of Zr4+. CYCTZO ceramics with x=0.010 exhibited a relatively high εr value of 1.02×105 at 1kHz. Meanwhile, the improved grain boundaries response and dielectric properties were closely related to the strengthened grain boundaries resistance (Rgb). The present results indicate that the εr was improved and the tanδ was reduced by doping Zr4+ donors in Ca0.97Y0.03Cu3Ti4O12 (CYCTO) ceramics and explained that the electrical properties were closely related to the electrical heterogeneity of ceramic grains and grain boundaries.

Study on Ferroelectric and Dielectric Properties of Zr-Doped Sr2Bi4Ti5O18 Ceramics

2010 ◽  
Vol 105-106 ◽  
pp. 248-251 ◽  
Author(s):  
Ji Gong Hao ◽  
Zhi Jun Xu ◽  
Rui Qing Chu ◽  
Yan Jie Zhang ◽  
Qian Chen ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Electrical Properties ◽  
Single Phase ◽  
Piezoelectric Properties ◽  
Ferroelectric Ceramics ◽  
Sem Images ◽  
Ceramic Samples ◽  
Xrd Patterns ◽  
Curie Temperature Tc ◽  
Ferroelectric And Piezoelectric Properties

Zr-doped Sr2Bi4Ti5O18 (SBTi) bismuth layer-structured ferroelectric ceramics were prepared and studied. XRD patterns revealed that all the ceramic samples were single phase compounds. SEM images showed that dense microstructures with uniform gain size were obtained in all samples. The effects of Zr4+ doping on the dielectric, ferroelectric and piezoelectric properties of SBTi ceramics were also investigated. It was found that Zr4+ dopant gradually decreased the Curie temperature (Tc), enhanced the remnant polarization (2Pr) and decreased the coercive field (Ec) of SBTi ceramics. Furthermore, the piezoelectric properties of the SBTi ceramics were improved by enlarging the content of Zr. The SBTi ceramics with 4 mol% of Zr4+ dopant exhibited good electrical properties: d33 = 21 pC/N, 2Pr = 14.3 μC/cm2, Tc = 251°C, εr = 376, tanδ = 1.8%.

Preparation of MgAl2O4 Transparent Nano-Ceramics and their Light Transmission Properties

2007 ◽  
Vol 336-338 ◽  
pp. 2296-2299 ◽  
Author(s):  
Jian Qi Qi ◽  
Tie Cheng Lu ◽  
Xiang Hui Chang ◽  
Mu Yun Lei ◽  
Cun Xin Huang
Keyword(s):  
Light Transmission ◽  
Ultrahigh Pressure ◽  
Light Transmittance ◽  
Affecting Factors ◽  
Pressure Source ◽  
Transmission Properties ◽  
Grain Sizes ◽  
Nano Powder ◽  
Ceramic Samples ◽  
Sintering Method

MgAl2O4 transparent nano-ceramic samples have been successfully prepared by ultrahighpressure- sintering method. The ultrafine MgAl2O4 nano-powder was obtained by high-temperaturecalcination method. The samples were sintered at relatively low temperatures (540, 620 and 700°C) under ultrahigh pressures (3, 3.7 and 5GPa) with a six-pressure-source and hexahedral anvil machine that is customarily used for diamond synthesis. The average grain sizes of the prepared samples range from 50 to 75nm. All of the samples sintered under different conditions are transparent. The sample sintered at 620°C under 3.7GPa has the highest density as well as the highest light transmittance (about 50%) at 1300 ~ 1700 nm. The results showed that the ultrahigh-pressure-sintered samples exhibit unique light transmission properties though their densities are not much higher (<97%), compared to the samples, of which densities are higher (>99.5%), obtained by conventional hot-pressing or hot isotopic pressing sintering methods. The light transmittance, its affecting factors and transparent mechanism of the MgAl2O4 samples have been discussed.

scholarly journals Structural, microstructural and dielectric characterizations of (Bi0.5Na0.5)TiO3based lead-free ferroelectric ceramics

2021 ◽  
pp. 2140006
Author(s):  
B. R. Moya ◽  
A. C. Silva ◽  
A. Peláiz-Barranco ◽  
J. D. S. Guerra
Keyword(s):  
Lead Free ◽  
Ferroelectric Ceramics ◽  
Reaction Sintering ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Porosity Level ◽  
X Ray ◽  
Ceramic Samples ◽  
Lead Free Ceramics ◽  
Sintering Method

(1–[Formula: see text]Bi[Formula: see text]Na[Formula: see text]TiO3–[Formula: see text]BaTiO3 lead-free ceramics have been obtained from the conventional solid-state reaction sintering method. The structural properties were investigated from X-ray diffraction and Raman spectroscopy techniques. Results revealed well-crystallized ceramic samples with perovskite structure. Microstructural properties, obtained from scanning electron microscopy measurements, have shown high density with very low porosity level. The dielectric response, analyzed as a function of the temperature and several frequencies, showed very broad peaks with a strong frequency dependence of the temperature for the maximum dielectric permittivity for the modified system. Results were analyzed considering the influence of the BaTiO3 content on the studied physical properties.

Dielectric Properties of Zn-Doped CCTO Ceramics by Sol-Gel Method

2011 ◽  
Vol 197-198 ◽  
pp. 302-305 ◽  
Author(s):  
Dong Xu ◽  
Chen Zhang ◽  
Xiao Nong Cheng ◽  
Yuee Fan ◽  
Tao Yang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Single Phase ◽  
Sol Gel ◽  
Sharp Decrease ◽  
Dielectric Constants ◽  
Doping Amount ◽  
Xrd Pattern ◽  
Gel Method ◽  
Sol Gel Method

The CaCu3-xZnxTi4O12(CCZTO) (x=0, 0.06, 0.1, 0.2) ceramics were prepared by Sol–gel method. The XRD pattern shows that crystal structure of the sample with no Zn is basically single-phase. The SEM results indicate that the samples have porous structures and the gain size decreases with the content of Zn increasing. The dielectric properties of CCZTO were analyzed by Agilent 4294A. The experimental results show that the dielectric constants are less than that in other papers reported obviously because of their mesoporous structures. With the little doping amount(x=0.06, 0.1), a sharp decrease happened in the dielectric constant (εr). The higher εrwas found when x=0.2, but its dielectric loss (D) had greatly increased and frequency stability of dielectric property became worse. The uniformity of gains was put forward to explain the results which showed great impact on the dielectric constant.

Effect of Ni2+substitution on the Structural, Magnetic and Dielectric Properties of PbFe12-xNixO19 Nanoparticles

2020 ◽  
Author(s):  
seyed ebrahim Mousavi Ghahfarokhi ◽  
Foruzan Bazdar ◽  
Iraj Kazeminezhad ◽  
Elham Mohammadzadeh Shobegar
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Properties ◽  
Single Phase ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Sem Images ◽  
Ac Electrical Conductivity ◽  
Field Frequency ◽  
Magnetic And Dielectric Properties ◽  
Lcr Meter

Abstract PbFe12-xNixO19 nanoparticles (x = 0-1) were prepared by a sol–gel method. The influence of Ni2+ substitution on structural, magnetic and dielectric properties of PbFe12O19 nanoparticles was investigated. The samples of PbFe12-xNixO19 nanoparticles have been characterized by the X-ray diffractomere (XRD), Fourier transform infrared spectrometer (FT-IR), scanning electron spectrometer (SEM), vibrating sample magnetometer (VSM), and an LCR meter. The results reveal that PbFe12-xNixO19 compounds up to x = 0.2 are single phase. The bands of absorption in the 400– 500 cm-1 and the bands of absorption in the range of 500 -600 cm-1, corresponding to the formation of octahedral and tetrahedral sites which confirms the presence of metal– oxygen stretching band in ferrites. Also, SEM images show that by increasing Ni2+ doping grains size have been increased. However, for x > 0.2, the secondary Ni spinel ferrite (NiFe2O4) appears which the saturation magnetization and magnetic coercivity decreases. In addition, Ni2+substitution reduces the dielectric constant, dielectric loss, and ac electrical conductivity for all samples decrease rapidly with increasing applied field frequency and reaches a constant value beyond a certain frequency which this is characteristic of the normal dielectric behaviour of ferrites and has been investigated by Maxwell–Wagner’s two-layer model and Koop’s theory. The variation in ac conductivity (σac) with frequency shows that the electrical conductivity in these ferrites is mainly attributed to the electron hopping mechanism.Therefore; all single-phase Ni2+ substituted samples are suitable for use in magnetic recording media and microwave devices.

scholarly journals Technology and electrophysical properties of Mn4+, Sb3+, Dy3+ and W6+ -doped Pb(Zr0.49Ti0.51)O3 ceramics

2018 ◽  
Vol 242 ◽  
pp. 01001
Author(s):  
Dariusz Bochenek ◽  
Ćwikiel Ewa ◽  
Przemysław Niemiec ◽  
Tomasz Goryczka
Keyword(s):  
Dielectric Properties ◽  
Electric Conductivity ◽  
Mixed Oxide ◽  
Piezoelectric Transducers ◽  
Pressureless Sintering ◽  
Electrophysical Properties ◽  
Conductivity Measurements ◽  
Ceramic Powders ◽  
Ceramic Samples ◽  
Sintering Method

In paper three multicomponent PZT-type ceramics doped by Mn4+, Sb3+, Dy3+, W6+ have been prepared by the conventional mixed oxide method. The multicomponent PZT-type ceramic powders were synthetized by calcining route, while densification was carried out by pressureless sintering method. The paper presents XRD, SEM, EDS, dielectric and DC electric conductivity measurements of the multicomponent PZT-type ceramic samples. Conducted tests indicate obtained multicomponent PZT-type exhibit good dielectric properties giving the possibility for their use as actuators and piezoelectric transducers in modern micromechatronic and microelectronic applications.

Li2ZnTi3O8 Microwave Dielectric Ceramics Prepared by the Reaction-Sintering Process

2015 ◽  
Vol 655 ◽  
pp. 164-167 ◽  
Author(s):  
Xu Sheng Hu ◽  
Guo Guang Yao ◽  
Xiu Lao Tian
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Reaction Sintering ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric ◽  
Pure Phase ◽  
Dielectric Ceramics ◽  
Sintering Method

Li2ZnTi3O8ceramics were prepared by reaction-sintering process (calcination free). The crystal phase and microstructure were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). A pure phase of Li2ZnTi3O8ceramics sintered at 1075 °C-1150 °C with cubic spinel structure was confirmed by XRD. The microwave dielectric properties (εr,Qxf) of Li2ZnTi3O8ceramics were strongly dependent on the densification and grain size. The τfof Li2ZnTi3O8ceramics was almost independent with the sintering temperatures. In particular, Li2ZnTi3O8ceramics by reaction-sintering method sintered at 1125 °C for 5 h exhibited good combination microwave dielectric properties of εr=21.7, Q×f=70 500 GHz (at 7.5 GHz) and τf=-13 ppm/°C.

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