Processing and Properties of Ferroelectric Bi4-x La xTi3O12 Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 106-108
Author(s):  
Wen Wang ◽  
Hua Ke ◽  
Deng Guo Zhang ◽  
De Chang Jia ◽  
Yu Zhou
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Solid Phase ◽  
Sol Gel ◽  
Cold Isostatic Pressing ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Doping Content ◽  
La Doping ◽  
Reaction Processes

Bi4-xLaxTi3O12 (BLT, x=0, 0.75, 1, 2) ceramic powders were prepared with sol-gel and solid phase reaction processes, respectively. BLT powders were synthesized after decarbonization at 300°C for 1h followed by calcination at 800°C for 2h. The ceramics synthesized with cold isostatic pressing and sintering at 1150°C exhibit a perovskite-like structure. The influence of sintering parameters and La doping content on density, microstructure and dielectric properties of the BLT were discussed. With the increase of La doping content in Bi4-xLaxTi3O12, dielectric constant increases and dielectric loss gradually decreases. The dielectric constant and dielectric loss of Bi4-xLaxTi3O12 (x=2) are 132.7 and 0.012 at 100 KHz, respectively.

The Dielectric Characteristics of Sr and Mg Doped CCTO Ceramics

2011 ◽  
Vol 687 ◽  
pp. 416-421 ◽  
Author(s):  
Qiu Xiang Liu ◽  
Xin Gui Tang ◽  
Yan Ping Jiang ◽  
F. L. Dong
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Solid Phase ◽  
Complex Impedance ◽  
Impedance Analysis ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Practical Applications ◽  
Complex Impedance Analysis ◽  
Mg Doped

Two kinds ceramics of pure CaCu3Ti4O12 (CCTO) and Sr/Mg doped (Ca0.25Cu0.75)0.5Sr0.5TiO3 + xMgO (x=0.01, 0.03, 0.05, 0.1, denoted as CCST-M-1, CCST-M-3, CCST-M-5, CCST-M-10, respectively) were prepared using the traditional solid phase reaction method. The dielectric properties were measured by HP 4194A Impedance/Gain-Phase Analyzer with the frequency range from 100 Hz to 1MHz. The temperature dependence of dielectric constant and loss tangent were measured for different frequencies. The variation relation of the critical temperature with the frequency was fitted theoretically which is in agreement with the Arrhenius law for pure CCTO. According to a variable power law to describe the paraelectric dielectric constant of ferroelectrics with diffuse phase transitions, the theoretical fitting was carried out for doped samples, and it was suggested that all doped samples exhibited the Debye-like relaxation. Among the doped and pure CCTO samples, CCST-M-1 was of the lowest dielectric loss at the whole measurement frequency, and whose I–V response curve was nonlinear suggesting a non-ohmic contact. The complex-impedance analysis results showed that the reduction in dielectric loss of CCST-M-1 sample can be attributed to the increase of grain boundary resistance. It is expect that these results are helpful to promote the CCTO-related materials to practical applications.

Characterizations of Tb:Zn 2 SiO 4 films on silicon wafer prepared by sol-gel dip-coating and solid-phase reaction

2004 ◽  
Vol 13 (4) ◽  
pp. 561-563 ◽  
Author(s):  
Ji Zhen-Guo ◽  
Zhao Shi-Chao ◽  
Xiang Yin ◽  
Song Yong-Liang ◽  
Ye Zhi-Zhen
Keyword(s):  
Silicon Wafer ◽  
Solid Phase ◽  
Sol Gel ◽  
Dip Coating ◽  
Solid Phase Reaction ◽  
Phase Reaction

Needle-Like Mullite Ceramic Prepared by Sol-Gel Process

2011 ◽  
Vol 233-235 ◽  
pp. 2640-2643 ◽  
Author(s):  
Fu Sheng Song
Keyword(s):  
Powder Diffraction ◽  
Solid Phase ◽  
Raw Materials ◽  
Sol Gel ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Mullite Ceramic ◽  
X Ray ◽  
Sol Gel Process ◽  
Ceramic Blocks

Using tetraethoxysilane, aluminum nitrate and aluminum fluoride as raw materials, the precursor of mullite was prepared by sol-gel process. When the precursor sintered at 1200°C, mullite ceramic was obtained. Differential thermal analysis, X-ray powder diffraction and scanning electron microscope were used to characterize the dried mullite gel and ceramic blocks. The results suggest mullite is synthesized by solid-phase reaction mechanism. X-ray powder diffraction indicates mullite is the main crystals phase in the ceramic specimen. SEM micrograph shows the mullite grains in the shape of short rod with length of 20 um when sintered at 1200 °C for 2 h and the grains grown up to acicular with length of more than 50 um when the treating time under 1200 °C achieved to 4 h.

Preparation of complex oxide (Pr0.8Y0.2)0.6Ca0.4CoO3 from Pr–Y–Ca–Co gel synthesized by ultrasonic irradiation and its metal-insulator transition characteristics

2021 ◽  
Author(s):  
masahiro tahashi ◽  
Akikazu Nanbu ◽  
Hiroyuki Yamada ◽  
Makoto Takahashi ◽  
Hideo Goto ◽  
...  
Keyword(s):  
Ultrasonic Irradiation ◽  
Solid Phase ◽  
Sol Gel ◽  
Synthesis Method ◽  
Complex Oxide ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Metal Insulator ◽  
Good Crystallinity ◽  
Poorly Soluble

Abstract We previously reported that a swollen gel possessing a uniform composition and prolonged stability can be conveniently prepared by simple ultrasonic irradiation of an ethanol suspension of calcium acetate, which is poorly soluble in ethanol. In this study, the same gel synthesis method was applied to prepare the multicomponent oxide (Pr1−yYy)1−xCaxCoO3 (PYCCO), which undergoes a metal-insulator phase transition. Calcination of the Pr–Y–Ca–Co swollen gel at 800 °C for 12 h in air afforded PYCCO nanoparticles with good crystallinity, representing a faster and more convenient route compared with conventional solid-phase reaction methods or sol–gel methods.

The preparation of Zn2+-doped TiO2 nanoparticles by sol–gel and solid phase reaction methods respectively and their photocatalytic activities

Chemosphere ◽  
2005 ◽  
Vol 59 (9) ◽  
pp. 1367-1371 ◽  
Author(s):  
Guoguang Liu ◽  
Xuezhi Zhang ◽  
Yajie Xu ◽  
Xinshu Niu ◽  
Liqing Zheng ◽  
...  
Keyword(s):  
Tio2 Nanoparticles ◽  
Solid Phase ◽  
Sol Gel ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Doped Tio2 ◽  
Photocatalytic Activities

Effect of Sr Doping on Piezoelectric Properties of Pb(Mn1/3Nb2/3)O3-Pb(Zr,Ti)O3 Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 201-204
Author(s):  
Bao Shan Li ◽  
Guo Rong Li ◽  
Zhi Gang Zhu ◽  
Wang Zhong Zhang ◽  
Qing Rui Yin ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Oxygen Vacancies ◽  
Piezoelectric Properties ◽  
Sintering Temperature ◽  
Solid Phase ◽  
Coupling Factor ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Pzt Ceramics

This paper aims at the determination of the effects of strontium addition on the microstructural evolution and the piezoelectric properties for Pb(Mn1/3Nb2/3)O3-Pb(Zr,Ti)O3 (PMnN-PZT) ceramics. The Sr content was chosen in the range of 2-8 mol%. These materials were prepared by the solid phase reaction of the oxides. It was found, from the experimental results, the tetragonality of the PMnN-PZT lattice and the Curie temperature decreased with Sr content; in the meantime, dielectric constant increased greatly. Dielectric constant (er) and planar coupling factor (Kp) was proven to be dependent on sintering temperature. P-E curves of PMnN-PZT system exhibited some “pinched” shape instead of the normal square-like P-E loops, illustrating presence of the oxygen vacancies by reason of the preferable substitution of the B-sites ion.

Ultrathin Dielectric Films Grown by Solid Phase Reaction of Pr with SiO2

2004 ◽  
Vol 811 ◽  
Author(s):  
Hans-Joachim Müssig ◽  
Jarek Dąbrowski ◽  
Christian Wenger ◽  
Grzegorz Łupina ◽  
Roland Sorge ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Solid Phase ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Dielectric Films ◽  
Solid Phase Reaction ◽  
Phase Reaction

ABSTRACTWe have fabricated Pr-based high-k gate dielectric films by physical vapor deposition of metallic Pr on SiO2 under ultra-high vacuum (UHV) conditions at room temperature, followed by oxidation and annealing steps. The films have been analyzed by electrical measurements, X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM). Some insight into the physical processes involved has been obtained from ab initio calculations. The high-k gate stacks consist of a SiO2-based buffer with an enhanced dielectric constant and a Pr silicate barrier with a high dielectric constant. The role of the buffer is to preserve the high quality of the SiO2/Si(001) interface, and the role of the barrier is to keep the tunneling currents low by increasing its physical thickness. A Pr film deposited on a 1.8 nm SiO2 layer, oxidized at room temperature by air, and annealed in N2 atmosphere with O2 partial pressure of 10−3 mbar results in a stack with the Capacitance Equivalent Thickness of 1.5 nm and leakage of 10−4 A/cm2.

scholarly journals Fe3O4@C Nanoparticles Synthesized by In Situ Solid-Phase Method for Removal of Methylene Blue

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 330
Author(s):  
Hengli Xiang ◽  
Genkuan Ren ◽  
Yanjun Zhong ◽  
Dehua Xu ◽  
Zhiye Zhang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Solid Phase ◽  
Raw Materials ◽  
Phase Method ◽  
Maximum Adsorption Capacity ◽  
High Catalytic Activity ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
High Concentrations

Fe3O4@C nanoparticles were prepared by an in situ, solid-phase reaction, without any precursor, using FeSO4, FeS2, and PVP K30 as raw materials. The nanoparticles were utilized to decolorize high concentrations methylene blue (MB). The results indicated that the maximum adsorption capacity of the Fe3O4@C nanoparticles was 18.52 mg/g, and that the adsorption process was exothermic. Additionally, by employing H2O2 as the initiator of a Fenton-like reaction, the removal efficiency of 100 mg/L MB reached ~99% with Fe3O4@C nanoparticles, while that of MB was only ~34% using pure Fe3O4 nanoparticles. The mechanism of H2O2 activated on the Fe3O4@C nanoparticles and the possible degradation pathways of MB are discussed. The Fe3O4@C nanoparticles retained high catalytic activity after five usage cycles. This work describes a facile method for producing Fe3O4@C nanoparticles with excellent catalytic reactivity, and therefore, represents a promising approach for the industrial production of Fe3O4@C nanoparticles for the treatment of high concentrations of dyes in wastewater.

Microstructure and Microwave Dielectric Properties of BaTi4O9 Ceramics Derived from a Sol-Gel Precursor

2011 ◽  
Vol 326 ◽  
pp. 127-130
Author(s):  
Xian Li Huang ◽  
Fu Ping Wang ◽  
Ying Song
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Sol Gel ◽  
Microwave Dielectric Properties ◽  
Sintering Process ◽  
Temperature Coefficients ◽  
Microwave Dielectric ◽  
Ceramic Samples ◽  
Quality Factor Q

In the present work, the microstructure and microwave dielectric properties of BaTi4O9 ceramics derived from a sol-gel precursor were presented. Density measuring results demonstrated that the largest densities of ceramic sample about 96.7% could be reached by virtue of a cool iso-static press and a sintering process at at 1300 °C for 6 hours. The dielectric constant (εr), quality factor (Q×f) and the temperature coefficients (τf) of the BaTi4O9 ceramic samples were 36.65, 28000 GHz, +20.2 ppm/°C, respectively. XRD, SEM and XPS were used to characterize the microstructure of the ceramics samples. Substantial Ti3+ was proposed to be the cause of dielectric loss.

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