Consolidation and properties of Gd0.1Ce0.9O1.95 nanoparticles for solid-oxide fuel cell electrolytes

2006 ◽  
Vol 21 (1) ◽  
pp. 119-124 ◽  
Author(s):  
A.I.Y. Tok ◽  
L.H. Luo ◽  
F.Y.C. Boey ◽  
J.L. Woodhead
Keyword(s):  
Grain Size ◽  
Ionic Conductivity ◽  
Sintering Temperature ◽  
Spherical Shape ◽  
Impedance Analysis ◽  
Lattice Parameter ◽  
Narrow Particle Size Distribution ◽  
Precipitation Process ◽  
Boundary Area ◽  
Co Precipitation

Gd-doped ceria solid solutions have been recognized to be leading electrolytes for use in intermediate-temperature fuel cells. In this paper, the preparation, solubility, and densification of Gd0.1Ce0.9O1.95 ceramics derived from carbonate co-precipitation are reported. The dissolution of Gd2O3 in CeO2 lattice was identified to be completed during the co-precipitation process by studying the lattice parameter as a function of temperature. After calcination at 800 °C for 2 h, the nano-sized Gd0.1Ce0.9O1.95 powder (∼33 nm) with a nearly spherical shape and a narrow particle-size distribution was obtained. This calcined powder has high sinterability and maximum densification rate at ∼1000 °C. Sintering at 1300 °C for 4 h yielded over 97% relative density with near maximum. The grain size increased with increases in sintering temperature. The ionic conductivity of these pellets was tested by alternating current impedance spectroscopy to elucidate the contribution of intragranular and intergranular conductivity to the total ionic conductivity. It was found that sintering temperature does not affect intragranular conductivity, though intergranular conductivity was strongly influenced by grain size, grain boundary area, and relativity density. This pellet sintered at 1500 °C for 4 h showed a high ionic conductivity of 5.90 × 10−2 s/cm when measured at 750 °C. The characterization and structural evaluation of the as-received powders were carried out using x-ray diffraction, transmission electron microscopy, Brunauer–Emmett–Teller, and dilatometer and impedance analysis.

Effect of Grain Size on the Luminescent Properties of Nano-Scale Gd2O3:Eu

2005 ◽  
Vol 23 ◽  
pp. 15-18 ◽  
Author(s):  
Qing Feng Liu ◽  
Qian Liu
Keyword(s):  
Grain Size ◽  
Luminescent Properties ◽  
Combustion Method ◽  
Lattice Parameter ◽  
Precipitation Process ◽  
Micro Scale ◽  
Grain Sizes ◽  
Nano Scale ◽  
Co Precipitation ◽  
Uv Excitation

Nano-scale Gd2O3:Eu phosphor powders were synthesized by combustion method. In this process, the grain sizes of nano-scale Gd2O3:Eu were controlled by changing the amount of citric acid. Compared with micro-scale powders obtained from co-precipitation process, XRD revealed that the lattice parameter of nano-scale powders Gd2O3:Eu decreased. Further detailed study show that the luminescent properties were related to the grain size of nano Gd2O3:Eu powders under UV excitation.

Upshot of Concentration of Zirconium (IV) Oxynitrate Hexa Hydrate on Preparation and Analyses of Zirconium Oxide (ZrO2) Nanoparticles by Modified Co-Precipitation Method

2021 ◽  
Vol 21 (11) ◽  
pp. 5707-5713
Author(s):  
M. Ramachandran ◽  
R. Subadevi ◽  
P. Rajkumar ◽  
R. Muthupradeepa ◽  
R. Yuvakkumar ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Complex Impedance ◽  
Impedance Analysis ◽  
Raw Material ◽  
Precipitation Method ◽  
Zro2 Nanoparticles ◽  
Fixed Amount ◽  
Complex Impedance Analysis ◽  
Dta Analysis ◽  
Co Precipitation

In the present work, pure nanocrystalline monoclinic Zirconia (ZrO2) has been successfully synthesized and optimized by the modified co-precipitation method. The concentration of raw material has been optimized with the fixed amount of precipitation agent (Potassium hydroxide KOH). The thermal history of the precursor has been examined through TG/DTA analysis. All the samples are subjected to study the structure, fingerprints of the molecular vibrations, and morphology analyses. The representative sample has been analyzed through Transmission Electron Microscope (TEM) and X-ray Photo Electron Spectroscopy (XPS) analyses. The as-prepared sample exhibits the better crystallinity and surface morphology with lesser particle size (190 nm) when the raw material concentration is 0.2 M. The as-prepared ZrO2 filler (0, 3, 6, 9, and 12 wt.%) is spread through the enhanced polymer electrolyte P(S-MMA) (27 Wt.%)-LiClO4 (8 wt.%)-EC + PC (1;1 of 65 wt.%) complex system via solution casting method. The as-synthesized electrolyte films are examined via complex impedance analysis. P(S-MMA) (27 wt.%)-LiCIO4 (8 wt.%)-EC + PC (1 ;1 of 65 wt.%)-6 wt.% of ZrO2 shows the high ionic conductivity 2.35 × 10–3 Scm–1. Temperature-dependent ionic conductivity studies obey the non-linear behavior. The enhanced ZrO2 has been expected to enhance the other electrochemical properties of the lithium secondary battery.

Sintering behavior and ionic conductivity of Li1.5Al0.5Ti1.5(PO4)3 synthesized with different precursors

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bambar Davaasuren ◽  
Qianli Ma ◽  
Alexandra von der Heiden ◽  
Frank Tietz
Keyword(s):  
Grain Size ◽  
Solid State ◽  
Ionic Conductivity ◽  
Solid State Reaction ◽  
Sintering Temperature ◽  
Sintering Behavior ◽  
Homogeneous Microstructure ◽  
Micro Cracks ◽  
Primary Particles ◽  
Total Ionic Conductivity

Abstract Li1.5Al0.5Ti1.5(PO4)3 (LATP) powders were prepared from different NO x -free precursors using an aqueous-based solution-assisted solid-state reaction (SA-SSR). The sintering behavior, phase formation, microstructure and ionic conductivity of the powders were explored as a function of sintering temperature. The powders showed a relatively narrow temperature windows in which shrinkage occurred. Relative densities of 95% were reached upon heating between 900 and 960 °C. Depending on the morphological features of the primary particles, either homogeneous and intact microstructures with fine grains of about <2 µm in size or a broad grain size distribution, micro-cracks and grain cleavages were obtained, indicating the instability of the microstructure. Consequently, the ceramics with a homogeneous microstructure possessed a maximum total ionic conductivity of 0.67 mS cm−1, whereas other ceramics reached only 0.58 mS cm−1 and 0.21 mS cm−1.

scholarly journals Effect of Sintering Temperature on the Microstructure, Electrical and Magnetotransport Properties of La0.67Sr0.33MnO3 Compound

2014 ◽  
Vol 895 ◽  
pp. 319-322
Author(s):  
Lim Kean Pah ◽  
Abdul Halim Shaari ◽  
Chen Soo Kien ◽  
Chin Hui Wei ◽  
Albert Gan ◽  
...  
Keyword(s):  
Grain Size ◽  
Single Phase ◽  
Sintering Temperature ◽  
Measurement Range ◽  
Hexagonal Structure ◽  
Precipitation Method ◽  
Metal Insulator ◽  
Higher Temperature ◽  
Co Precipitation ◽  
Grain Surface

In this work, we report the effect of sintering temperature (900°C, 1000°C, 1100°C and 1200°C) on the electrical and magnetotransport properties of polycrystalline La0.67Sr0.33MnO3 (LSMO). Single phase of LSMO hexagonal structure (R-3c) accompanied with minor phases was successfully synthesized by co-precipitation method. With increasing sintering temperature, grain growth was promoted and grain connectivity was improved. It was found that an enhancement of resistivity on smaller grain size was due to larger grain surface over volume (grain boundaries effect). The shifting of the metal-insulator transition (TMI) to higher temperature was also responsible for observed changes in physical properties. TMI of 900°C, 1000°C and 1100°C were 232 K, 278 K and 298 K respectively however 1200°C was out of measurement range (higher than 300 K). In summary, CP900 with smaller grain size distribution (~200 nm) displayed the highest resistivity and MR% of -19.2% (at 80 K, 10 kG).

scholarly journals Crystallographic and optical studies on Cr doped ZnS nanocrystals

Cerâmica ◽  
2014 ◽  
Vol 60 (355) ◽  
pp. 425-428 ◽  
Author(s):  
M. R. Bodke ◽  
Y. Purushotham ◽  
B. N. Dole
Keyword(s):  
Grain Size ◽  
Fourier Transforms ◽  
Chemical Species ◽  
Lattice Parameter ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Cubic Form ◽  
Zns Nanocrystals ◽  
Cr Concentration ◽  
Co Precipitation

Chromium doped ZnS nanocrystals with pure and 10% compositions were synthesized by chemical co-precipitation route. Samples were characterized by X-ray diffraction (XRD) technique, Fourier transforms infrared spectroscopy (FTIR) and UV-Visible spectrometer. Lattice parameter 'a' decreases and grain size increases with increasing Cr concentration. XRD study shows that both the samples have cubic structure. Grain size increases due to ionic radius. The functional groups and chemical species of Cr doped ZnO samples were determined using FTIR data. UV-Vis study revealed that red shift is clearly observed in absorption band. Surface morphology of pure and 10% Cr doped samples was investigated by SEM technique and it is confirmed that images exibit cubic form of the samples. Using EDS, percentage of chemical compositions of material recorded.

Co-Precipitation of 5-Fluorouracil and Poly(L-Lactide) Using Solution-Enhanced Dispersion by Supercritical CO2

2007 ◽  
Vol 342-343 ◽  
pp. 477-480
Author(s):  
Xi Ming Pu ◽  
Yun Qing Kang ◽  
Ai Zheng Chen ◽  
Li Liao ◽  
Guang Fu Yin
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Supercritical Co2 ◽  
Smooth Surface ◽  
Spherical Shape ◽  
Narrow Particle Size Distribution ◽  
Effective Technique ◽  
Composite Microspheres ◽  
Co Precipitation

5-Fluorouracil-poly(L-lactide) (5-Fu-PLLA) microspheres have been co-precipitated in a process namely solution-enhanced dispersion by supercritical CO2 (SEDS). First, the 5-Fu is successfully micronized and then used to produce the 5-Fu-PLLA microspheres. The 5-Fu-PLLA microspheres synthesized in the SEDS process exhibited a rather spherical shape, smooth surface, and a narrow particle size distribution, where it ranged from 531 nm to 1280 nm, with a mean particle size of 793 nm. The dichloromethane residue in the 5-Fu-PLLA microspheres is 46 ppm. The average drug load of the 5-Fu-PLLA microspheres is 12.7%. The results of this study indicate that the SEDS process is an effective technique to co-precipitate 5-Fu and PLLA as composite microspheres.

Influence of Pre-Sintering Temperature and Time on the Properties of YIG Target

2012 ◽  
Vol 476-478 ◽  
pp. 1150-1153 ◽  
Author(s):  
Hui Zheng ◽  
Jiang Xia Deng ◽  
Liang Zheng ◽  
Hui Bin Qin ◽  
Jun Wu ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Property ◽  
Size Distribution ◽  
Crystallization Temperature ◽  
Sintering Temperature ◽  
Precipitation Method ◽  
Fine Grained ◽  
Good Magnetic Property ◽  
Measurement Results ◽  
Co Precipitation

The influence of pre-sintering temperature and time, which ranged from 700 to 900°C and from 0.5 to 12h respectively, on the size and shape of the grains composed of YIG target were studied. The YIG precursors, of which the crystallization temperature was obtained by the DSC tests, were synthesized through the chemical co-precipitation method. According to the XRD, SEM and VSM measurement results, YIG powders pre-sintered at 750°C for 7hours, which temperature is lower than the crystallization temperature, can make the target with the highest density, good magnetic property, fine-grained and narrow grain size distribution.

Crystallographic Properties of Aluminum-Doped Barium Zirconium Titanate Thin Films by Sol Gel Process

2013 ◽  
Vol 789 ◽  
pp. 101-104 ◽  
Author(s):  
Rachmat Andika ◽  
Muhammad Hikam
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Ferroelectric Phase ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Lattice Parameter ◽  
Partial Substitution ◽  
Zirconium Titanate ◽  
Sol Gel Process ◽  
Barium Zirconium Titanate

We studied the crystallographic of Barium Zirconium Titanate thin films with Aluminum doped (BZAT). These films were prepared by sol-gel process and followed by spin coating. The sintering temperature is taken at 800°C and 900°C. We found that the crystallographic system of BZAT thin films have tetragonal structure with the lattice parameter slightly changed by various Aluminum partial substitution. When 0.01 Al moles added, the grain size of the films is 29.42 nm at 800°C. The sintering temperature 900°C increased the grain size into 50.95 nm. We also calculated the spontaneous polarization theoretically and we found the optimum value of BZT thin film with 0.01 mole Al heated at 800°C, is 0.143 C/m2. This way, we could predict that the film has ferroelectric phase.

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