scholarly journals Dielectric properties of the PFN ceramics obtained different chemical-wet technology and sintering by hot pressing method

2018 ◽  
Vol 242 ◽  
pp. 01002
Author(s):  
Dariusz Bochenek ◽  
Przemysław Niemiec
Keyword(s):  
Dielectric Properties ◽  
Hot Pressing ◽  
Sol Gel ◽  
Ceramic Powder ◽  
Pyrochlore Phase ◽  
Pressing Method ◽  
Iron Citrate ◽  
Ceramic Samples ◽  
Technology Process ◽  
Niobium Ethoxide

The paper shows three kinds of chemical-wet technology synthesis of the ferroelectric-ferrimagnetic PbFe1/2Nb1/2O3 materials and technology process of the ceramic samples sintered by hot pressing method. In the technological process of the PFN powders were used follows precursors: lead acetate trihydrate and niobium ethoxide while an iron-related components were changed: iron nitrate obtained by first sol-gel technology (PFN-n), iron oxalate obtained by second sol-gel technology (PFN-ox) and iron citrate obtained by third technology (PFN-c). XRD, SEM tests and temperature measurements of dielectric properties of the ceramic samples were carried out. The SEM microstructure tests of the PFN ceramic samples confirm the properly conducted technological processes. The best dielectric properties of the PFN ceramic samples were obtained for third technology using iron citrate precursor. But, this method of the PFN ceramic powder requires minimization of a pyrochlore phase and reduction porosity of the ceramic samples.

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.

Fabrication of Bi6Fe2Ti3O18 Ceramics by Mixed Oxide Method

2012 ◽  
Vol 730-732 ◽  
pp. 100-104
Author(s):  
Agata Lisińska-Czekaj
Keyword(s):  
Room Temperature ◽  
Ceramic Powder ◽  
Diffraction Method ◽  
Elementary Cell ◽  
X Ray Diffraction ◽  
Stoichiometric Mixture ◽  
Pressing Method ◽  
X Ray ◽  
Cell Parameters ◽  
Ceramic Samples

In the present study Bi6Fe2Ti3O18 (BFTO) ceramics has been fabricated by solid state reaction from the mixture of simple oxides viz. Bi2O3, TiO2 and Fe2O3. Stoichiometric mixture of the powders was thermally analyzed so parameters of the thermal treatment were determined. The EDS measurements have shown conservation of the chemical composition of the ceramic powder after calcination. Hot-pressing method was used for final densification of ceramic samples. The crystalline structure of the sintered samples was examined by X-ray diffraction method at room temperature. It was found that BFTO ceramics sintered at T=980 °C adopted the orthorhombic structure of Aba2 (41) space group with the following elementary cell parameters: a=5.4567(2)Å, b=49.418(2) and c=5.4826(2). Details concerning the atom’s positions are presented.

Effects of Doping ZnO-2B2O3-7SiO2 Glass by Sol-Gel Method on BaO-Sm2O3-4TiO2 Ceramics

2011 ◽  
Vol 148-149 ◽  
pp. 1077-1080
Author(s):  
Zhong Yan ◽  
Jin Liang Huang ◽  
Yong Jun Gu ◽  
Li Hua Li ◽  
Xiao Wang
Keyword(s):  
Dielectric Properties ◽  
Sol Gel ◽  
Ceramic Powder ◽  
Tungsten Bronze ◽  
Solid State Reaction Method ◽  
Structure Type ◽  
Conventional Solid State Reaction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Bst Ceramics

BaO-Sm2O3-4TiO2 (abbreviated BST) ceramic powder was prepared by the conventional solid-state reaction method. The effects of doping ZnO-2B2O3-7SiO2 (abbreviated ZBS) glass by sol-gel method on the sintering behaviors, microstructure, phase composition and dielectric properties of BST ceramics were investigated. The experimental results reveal that the main phase of samples doped with ZBS glass is tungsten bronze structure type BaSm2Ti4O12 phase, a litter Sm2Ti2O7 phase is also observed. The sintering tenperature of BST ceramics is remarkably reduced from 1350°C to 1050°C and the good dielectric properties of εr=60.2，tanδ=0.004，τf=-7.9ppm/°C were obtained for BST ceramics doped with 6wt% ZBS glass by sol-gel method sintered at 1050°C for 3h.

Nearly zero thermal expansion of β-spodumene glass ceramics prepared by sol–gel and hot pressing method

2012 ◽  
Vol 38 (6) ◽  
pp. 5315-5318 ◽  
Author(s):  
Long Xia ◽  
Xinyu Wang ◽  
Guangwu Wen ◽  
Bo Zhong ◽  
Liang Song
Keyword(s):  
Thermal Expansion ◽  
Hot Pressing ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Pressing Method

Synthesis and Structure of Sol-Gel Derived PST/Bi2Ti2O7 Composite Thin Films

2007 ◽  
Vol 336-338 ◽  
pp. 1400-1402
Author(s):  
Yong Lin Zhao ◽  
Pi Yi Du ◽  
Wen Jian Weng ◽  
Gao Rong Han
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Strontium Titanate ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Composite Thin Films ◽  
Impedance Analyzer ◽  
Gel Method ◽  
Ti Content

PST/Bi2Ti2O7 composite thin films were prepared by sol-gel method through heavily doping Bi3+ into lead strontium titanate (PST). The film with mono pyrochlore phase of Bi2Ti2O7 was also fabricated by controlling the Ti content in precursors. XRD, SEM and impedance analyzer measured the phase status, morphology and dielectric properties of the thin films, respectively. As a result, in the composite thin films, there was some Pb and Sr dissolved in Bi2Ti2O7, and the amount of dissolving ions decreased with the reduction of their composition in precursors. Bi4Ti3O12 impurity in crystalline Bi2Ti2O7 was due to the instability of Bi, and excess Ti in stoichiometry could make the film maintain to be mono pyrochlore phase. PST/Bi2Ti2O7 composite thin films had lower permittivity and lower dielectric loss than mono PST thin films.

Comparative Study of Synroc-C Ceramics Produced by Hot-Pressing and Inductive Melting

1996 ◽  
Vol 465 ◽  
Author(s):  
I. A. Sobolev ◽  
S. V. Stefanovsky ◽  
B. I. Omelianenko ◽  
S. V. Ioudintsev ◽  
E. R. Vance ◽  
...  
Keyword(s):  
Hot Pressing ◽  
Sol Gel ◽  
High Level Waste ◽  
Elemental Distribution ◽  
Pressing Method ◽  
Cell Parameters ◽  
Alloy Particles ◽  
Mineral Compositions ◽  
High Level ◽  
Simulated High Level Waste

ABSTRACTThree Synroc-C samples, containing simulated high level waste were studied. One was produced by the conventional hot-pressing method at ANSTO, Australia, and the others were obtained using cold crucible technology at Radon, Russia. One of the melted samples was prepared using the Australian sol-gel precursor and the second one was obtained from an oxide-nitrate mixture. It was established that the specimens have closely similar mineral compositions, with major hollandite, perovskite, zirconolite, and rutile. Small amounts of hibonite were also found. Unlike the hot-pressed Synroc containing metallic alloy particles, melted Synrocs contain molybdates. An investigation of mineral compositions and elemental distribution in the samples was carried out. Features of hot-pressed and melted ceramics were compared. Unit cell parameters of the Synroc phases were determined and preliminary results on durability of the melted Synroc are presented.

scholarly journals Preparation and properties of Bi-system high-Tc superconductors by hot-pressing method.

1991 ◽  
Vol 38 (2) ◽  
pp. 237-241 ◽  
Author(s):  
Masahiro Kojima ◽  
Yuuki Horata ◽  
Yuichi Ishikawa ◽  
Shuji Yoshizawa
Keyword(s):  
Hot Pressing ◽  
High Tc Superconductors ◽  
Pressing Method ◽  
High Tc

Influence of Ca-Doping on Structural, Magnetic and Dielectric Properties of Ba3Co2-xCaxFe24O41 Hexaferrite Powders

2015 ◽  
Vol 241 ◽  
pp. 226-236 ◽  
Author(s):  
Neha Solanki ◽  
Rajshree B. Jotania
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Sol Gel ◽  
Calcium Content ◽  
Combustion Method ◽  
Dielectric Behavior ◽  
Dielectric Parameters ◽  
Ca Doping ◽  
Auto Combustion ◽  
Magnetic And Dielectric Properties

Influence of Ca substitution on structural, magnetic and dielectric properties of Ba3Co2-xCaxFe24O41(where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0), prepared by Sol-Gel auto-combustion method, has been investigated in present studies. The obtained powder was sintered at 950 oC for 4 hrs. in the static air atmosphere. Structural analysis of Ca-doped Ba3Co2-xCaxFe24O41powders revealed pure Z-type hexaferrite phase at low temperature. The frequency dependent dielectric constant (Єʹ) and magnetic properties such as remanent magnetization (Mr), saturation magnetization (Ms) and coercivity (Hc) were studied. It is observed that coercivity increased gradually with increase in calcium content. The real dielectric constant (Єʹ) and dielectric loss tangent (tan δ) were studied in the frequency range of 20Hz to 2MHz. The dielectric parameters for all samples show normal dielectric behavior as observed in hexaferrites. Contents of Paper

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