Synthesis and Sintering of (K,Na)NbO3 Based Ceramics

2002 ◽  
Vol 755 ◽  
Author(s):  
Barbara Malic ◽  
Darja Jenko ◽  
Janez Bernard ◽  
Jena Cilensek ◽  
Marija Kosec
Keyword(s):  
Solid Solution ◽  
Thermal Decomposition ◽  
Dielectric Constant ◽  
Solid State ◽  
Powder Mixture ◽  
Niobium Oxide ◽  
Perovskite Phase ◽  
Solid State Synthesis ◽  
Theoretical Density

ABSTRACTStoichiometric K0.5Na0.5NbO3 solid solution(KNN) was prepared by solid-state synthesis from alkaline carbonates and niobium oxide. Thermal decomposition of the powder mixture occurs upon heating to 700 °C followed by crystallization of the perovskite phase. After sintering at 1100 °C, 2h the stoichiometric KNN reaches 94 % of theoretical density. Dielectric constant of stoichiometric KNN is 620, and the losses 0.03.

Solid state synthesis of ultrafine-LiCoO2 by enhanced thermal decomposition of carbonate precursors followed by double-calcining

2016 ◽  
Vol 289 ◽  
pp. 159-167 ◽  
Author(s):  
Yang Xuanye ◽  
Yan Hongge ◽  
Chen Jihua ◽  
He Mao ◽  
Xu Feng ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Solid State ◽  
Solid State Synthesis

Solid state synthesis, crystal growth and optical properties of urea and p-chloronitrobenzene solid solution

2016 ◽  
Vol 233 ◽  
pp. 244-251 ◽  
Author(s):  
R.N. Rai ◽  
Shiva Kant ◽  
R.S.B. Reddi ◽  
S. Ganesamoorthy ◽  
P.K. Gupta
Keyword(s):  
Solid Solution ◽  
Optical Properties ◽  
Crystal Growth ◽  
Solid State ◽  
Solid State Synthesis

The Influence of BaTiO3 Tetragonality by Solid State Synthesis on MLCC’s Dielectric Characteristics

2009 ◽  
Vol 421-422 ◽  
pp. 293-296
Author(s):  
Masayuki Hogiri ◽  
Hiroshi Kagata
Keyword(s):  
Particle Size ◽  
Dielectric Constant ◽  
Solid State ◽  
Relative Dielectric Constant ◽  
Solid State Synthesis ◽  
Core Shell ◽  
Dielectric Characteristics ◽  
Internal Electrode ◽  
Batio3 Powder ◽  
Dielectric Layers

BaTiO3 powders with particle size 0.1μm were made by solid state synthesis. To make high tetragonality BaTiO3 powder, mixture of TiO2 and BaCO3 was calcined in vacuum condition. And to make low tetragonality BaTiO3 powder, the mixture was calcined in air condition. With each powder, MLCCs with Ni-internal electrode were fabricated. Relationships between temperature and relative dielectric constant of MLCCs’ dielectric layers were analyzed and their dielectric grains were observed by TEM-EDS. As the result, MLCC made from high tetragonality BaTiO3 powder had good temperature characteristics and core-shell dielectric grains.

Preparation of Zirconia Base Solid Solution Nanopowder by Exothermal Solid-State Synthesis

2005 ◽  
Vol 88 (6) ◽  
pp. 1651-1654 ◽  
Author(s):  
Chuanyong Huang ◽  
Ruyan Guo ◽  
Zilong Tang ◽  
Zhongtai Zhang
Keyword(s):  
Solid Solution ◽  
Solid State ◽  
Solid State Synthesis ◽  
Base Solid Solution

Stabilization of mixed valencies in Cu, Zn-based oxides

2005 ◽  
Vol 891 ◽  
Author(s):  
Anne Le Nestour ◽  
Manuel Gaudon ◽  
Mona Tréguer-Delapierre ◽  
Ronn Andriessen ◽  
Alain Demourgues
Keyword(s):  
Solid Solution ◽  
Solid State ◽  
Solid State Synthesis ◽  
Zinc Aluminate ◽  
Absorption Bands ◽  
Absorption Properties ◽  
Nir Absorption ◽  
Uv Visible ◽  
Intense Absorption ◽  
Copper Cations

ABSTRACTCu and Zn-based oxides have been developed for the last decades because of their remarkable electronic properties and their relevant UV-Visible-NIR absorption properties. Cu in oxides can adopt various oxidation states (+I, +II, +III) stabilized in various environments (h, Td, D4h, C4v, D2h, Oh). Divalent copper cations can occupy Td or Oh sites in zinc aluminate spinel network. Solid state routes lead to homogeneous phases with Zn1−xCuxAl2O4 compositions. Depending on the inversion rate in the spinel matrix, various absorption bands have been identified in the UV-Visible-CNIR spectrum. The synthesis of the zinc-aluminate spinel solid solution Zn1−xCuxAl2O4 by an esterification route led to monocrystalline nanosized oxides. Two intense absorption bands at 300 and 500 nm can be attributed to charge transfer phenomena between oxygen and Cu2+ cations in tetrahedral and octahedral coordinations. Two other less intense absorption bands centred at 800 nm and 1500 nm are also appearing when the copper rate in the spinel increases but their relative intensity are not in good agreement with those observed in the case of the solid-state synthesis. In the case of the esterification route, the absorption band at 800 nm is much more intense than in the case of the solid-state synthesis. It can only be explained either by a deviation to the centrosymmetric character of octahedral sites or by the occurence of a non negligible amount of monovalent copper cations which give electronic transitions in this energy range. A magnetic study correlated to EPR measurements confirms the occurence of a mixed valence state for copper cations in the solid solution Zn1−xCuxAl2O4. EPR spectra at T=4K show for the small concentration of Cu2+ (x<0.10) a strong anisotropic signal due to the presence of Cu2+ ions in a distorted octahedral symmetry (gx=2.07, gy= 2.15 gz=2.23). Moreover the hyperfine structure, identified on EPR spectra tend to disappear as the compounds are annealed under air because the content of paramagnetic centers Cu2+ (3d9) as well as their interactions become significant. Furthermore, the color changes drastically with the Cu+ (3d10) content. Finally the structural features and UV-Visible-NIR absorption properties of copper-zinc aluminates will be discussed and compared to Cu-doped ZnO.

DIELECTRIC BEHAVIOUR OF MANGANESE MODIFIED STRONTIUM TITANATE CERAMICS SYNTHESIZED BY SOLID STATE CERAMIC ROUTE

2013 ◽  
Vol 22 ◽  
pp. 207-216
Author(s):  
PRAKASH SINGH ◽  
PRABHAKAR SINGH ◽  
OM PARKASH ◽  
DEVENDRA KUMAR
Keyword(s):  
Solid Solution ◽  
Dielectric Constant ◽  
Solid State ◽  
Space Charge ◽  
Single Phase ◽  
Dielectric Behaviour ◽  
Average Grain Size ◽  
State Ceramic ◽  
Solid State Ceramic Route ◽  
Ceramic Route

Various compositions with x=0.01, 0.05, 0.10, 0.20 and 0.30 in the system SrTi 1-x Mn x O 3 were prepared by solid state ceramic route. Compositions with x ≤ 0.10 were found to be single phase solid solution. In this paper, the result of investigations on the effect of manganese substitution in SrTiO 3 on dielectric behaviour for the compositions with x ≤ 0.10, which form single phase solid solution have been reported. Average grain size is small, this may be due to segregation of dopant at grainboundaries. Dielectric measurements were made in the temperature range 150–500K. Measurements of dielectric properties show that there is not much space charge polarisation across the grains and grainboundaries interface. This space charge polarisation only occurs at high temperature and one observes large dispersion of dielectric constant and dissipation factor. At low temperatures, dielectric behaviour follows the character of SrTiO 3 with only difference in the values of dielectric constant.

Electrical Properties of La2O3-Doped BaTiO3 Ceramics

2010 ◽  
Vol 148-149 ◽  
pp. 1222-1225
Author(s):  
Yan Jie Zhang ◽  
Wei Guo Fu ◽  
Xiang Yun Deng ◽  
Ren Bo Yang ◽  
Zhong Wen Tan ◽  
...  
Keyword(s):  
Solid Solution ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Solid State ◽  
Sintering Temperature ◽  
Lead Free ◽  
Defect Model ◽  
Maximum Value ◽  
Solid State Sintering

Hysteresis loop and dielectric properties of lead-free BaTiO3-La2O3 piezoelectric ceramics and BaTiO3 ceramic compared with pure BaTiO3 has been systematically studied. The amount of La2O3 addition ranged from 0.3~0.5mol% by controlling the sintering temperature. Dielectric properties of BaTiO3-La2O3 were promoted after the addition of La2O3, the maximum value of dielectric constant reached 8,624, recently. The role of La2O3 on the solid-state sintering of BaTiO3 is discussed on the basis of the solid-solution defect model.

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