Preparation and Charactorization of Superfine YAG Powder Materials via the Co-Precipitation Methods

2012 ◽  
Vol 164 ◽  
pp. 162-165 ◽  
Author(s):  
Jie Guang Song ◽  
Ai Xia Chen ◽  
Qiang Li ◽  
Zhi Wen Qiu ◽  
Jian Feng Zhou ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Functional Materials ◽  
Distribution Range ◽  
Precipitation Method ◽  
Sintering Behavior ◽  
Powder Materials ◽  
Co Precipitation

YAG is widely applied as the structure materials and the functional materials because of some excellent performances in the chemistry. The pure superfine YAG powder materials are prepared via the co-precipitation method after calcining the precursor of YAG at 1100°C. The superfine YAG powders has the better dispersion, the particle size distribution range is narrow bewteen 200 and 350nm. The superfine YAG mainly show near-spherical, and partly sintering behavior among the particles.

Study of the microstructure and particles of vanadium (III) oxide, vanadium (V) oxide and lithium aluminate powders

2020 ◽  
Vol 86 (1) ◽  
pp. 32-37
Author(s):  
Valeria A. Brodskaya ◽  
Oksana A. Molkova ◽  
Kira B. Zhogova ◽  
Inga V. Astakhova
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Vanadium Oxide ◽  
Size Distribution ◽  
Microstructural Analysis ◽  
Coherent Scattering ◽  
Powder Materials ◽  
Lithium Aluminate ◽  
Range Limit ◽  
Oxide Particles

Powder materials are widely used in the manufacture of electrochemical elements of thermal chemical sources of current. Electrochemical behavior of the powders depends on the shape and size of their particles. The results of the study of the microstructure and particles of the powders of vanadium (III), (V) oxides and lithium aluminate obtained by transmission electron and atomic force microscopy, X-ray diffraction and gas adsorption analyses are presented. It is found that the sizes of vanadium (III) and vanadium (V) oxide particles range within 70 – 600 and 40 – 350 nm, respectively. The size of the coherent-scattering regions of the vanadium oxide particles lies in the lower range limit which can be attributed to small size of the structural elements (crystallites). An average volumetric-surface diameter calculated on the basis of the surface specific area is close to the upper range limit which can be explained by the partial agglomeration of the powder particles. Unlike the vanadium oxide particles, the range of the particle size distribution of the lithium aluminate powder is narrower — 50 – 110 nm. The values of crystallite sizes are close to the maximum of the particle size distribution. Microstructural analysis showed that the particles in the samples of vanadium oxides have a rounded (V2O3) or elongated (V2O5) shape; whereas the particles of lithium aluminate powder exhibit lamellar structure. At the same time, for different batches of the same material, the particle size distribution is similar, which indicates the reproducibility of the technologies for their manufacture. The data obtained can be used to control the constancy of the particle size distribution of powder materials.

Modeling the Production Technology of Fully-Pressed Bi-Metal Powder Materials and Products

2021 ◽  
Vol 316 ◽  
pp. 570-575
Author(s):  
Badrudin G. Gasanov ◽  
Abakar B. Gasanov ◽  
Artem A. Aganov
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Bulk Density ◽  
Size Distribution ◽  
Metal Powder ◽  
Production Technology ◽  
Powder Mixture ◽  
Geometric Parameters ◽  
Powder Materials ◽  
Loading Devices

The features of calculating the thickness of the layers of bimetallic powder products without holes and the type of bushings are shown. The effect of the particle size distribution of the powders, the kinematic and geometric parameters of the loading devices and molds on the mechanism of the expiration of the powder mixture and on the thickness of the layers of the molded product is studied. A technique has been developed for determining the dimensions of the feeder cassette and tooling, depending on the overall dimensions and thicknesses of the working layers, in the production of whole-pressed bimetallic products on press machines with a vertical arrangement of layers. It was found that the thickness of each layer of bimetallic products depends on the geometric parameters of the feeder cassette and tooling, bulk density, particle size distribution and other characteristics of the powders, as well as on the speed of lowering the lower punch ν1 .

Effect of the Synthesis Method on the Properties of Ultrafine YAG Powder

2018 ◽  
Vol 281 ◽  
pp. 40-45
Author(s):  
Jie Guang Song ◽  
Lin Chen ◽  
Cai Liang Pang ◽  
Jia Zhang ◽  
Xian Zhong Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
Hydrothermal Reaction ◽  
Synthesis Method ◽  
Particle Morphology ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Synthesis Process ◽  
Powder Materials ◽  
Co Precipitation

YAG materials has a number of unique properties, the application is very extensive. In this paper, the superfine YAG powder materials were prepared by co-precipitation method and hydrothermal precipitation method. The influence of synthesis process on the morphology of the powder was investigated. The results showed that the precursor powder prepared via the co-precipitation method is mainly from amorphous to crystalline transition with the increasing calcination temperature, the precursor agglomeration is more serious, In the process of increasing the calcination temperature, the dispersibility of the roasted powder is greatly improved, which is favorable for the growth of the crystal grains, so that the particle size of the powder is gradually increased, the YAG precursor prepared by the co-precipitation method is transformed into YAG crystals, the phase transition occurs mainly between 900 and 1100°C. When the molar ratio of salt to alkali is Y3+: OH-=1: 8 via the hydrothermal reaction, the YAG particles with homogeneous morphology can be obtained. When the molar ratio of salt and alkali is increased continuously, the morphology of YAG particles is not obviously changed. The co-precipitation method is easy to control the particle size, the hydrothermal method is easy to control the particle morphology.

Synthesis the Precursor of LiNi0.5Mn0.5O2 via an Improved Carbonate Co-Precipitation

2011 ◽  
Vol 233-235 ◽  
pp. 32-35
Author(s):  
Yi Jie Gu ◽  
Yong Hu ◽  
Hong Quan Liu ◽  
Heng Hui Zhou ◽  
Zhen Guo ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Physical Characteristic ◽  
Electron Probe ◽  
Precipitation Method ◽  
Narrow Particle Size Distribution ◽  
Electron Probe Micro Analyzer ◽  
Secondary Particles ◽  
Co Precipitation ◽  
Line Analysis

Spherical Ni0.5Mn0.5CO3 is synthesized via carbonate co-precipitation method which uses NH4HCO3 as the precipitator. However, obvious agglomerate of secondary particles occurs when NH4HCO3 is used as the precipitator. The agglomerate particles can result in inferior physical characteristic. An improved carbonate co-precipitation which used NH4HCO3 doped with different proportion of NaOH as a new precipitator is tested in our study. Observed by SEM and Mastersizer, spherical morphology with narrow particle size distribution is synthesized with the proportion of NaOH reaches 10%. The element line analysis by Electron Probe Micro-analyzer shows symmetrical distributions of Ni and Mn elements via the improved carbonate co-precipitation.

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.

Contrasting Morphology of Calcium Phosphate Powders Prepared by the Wet Method Using Poly (Ethylene Glycol)

2008 ◽  
Vol 587-588 ◽  
pp. 32-36 ◽  
Author(s):  
Susana Dias ◽  
Vera Lourenço ◽  
Carlos A. Nogueira ◽  
Fernando A. Costa Oliveira
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Ethylene Glycol ◽  
Size Distribution ◽  
Particle Size Analysis ◽  
Precipitation Method ◽  
Size Analysis ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene ◽  
Experimental Findings

When preparing β-tricalcium phosphate (β-TCP), it is difficult to industrialise traditional methods because of the problem of particle aggregation. In this paper, β-TCP was prepared by calcining calcium-deficient hydroxyapatite (CDHA) powders obtained by the wet precipitation method at pH=6 and 40 °C, together with additions of poly (ethylene glycol) (PEG), in order to prevent powder agglomeration. The effect of the Ca/PEG mass ratio on the particle size distribution and the morphology of the resulting powders was evaluated. For comparison purposes, one powder without PEG addition was also synthesized. All synthesized powders were characterized by means of X-ray diffraction analysis, particle size analysis and scanning electron microscopy prior and after calcination in static air at 1000 °C for 15 h. Single-phase β-TCP powders have been obtained by calcining CDHA powders in the temperature range of 850°C-1150°C. It was also found that increasing the PEG content in solution decreased the particle size distribution of the agglomerated particles and the β→α-TCP transition temperature. A plausible explanation consistent with these experimental findings is proposed.

Effect of Process Parameters on the Particle Size Distribution of Paclitaxel Nanocrystals

2020 ◽  
Vol 12 (2) ◽  
pp. 137-146
Author(s):  
Gannimitta Arvind ◽  
Srinivas Prathima ◽  
Atla Venkateshwar Reddy
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Response Surface ◽  
Size Distribution ◽  
Process Parameters ◽  
Physicochemical Characteristics ◽  
Precipitation Method ◽  
Influence Of Process Parameters ◽  
Predicted Values ◽  
Two Phases

The main intention of this work was to study the effect of process variables on the particle size distribution of paclitaxel nanocrystals. Paclitaxel nanocrystals were prepared by using anti-solvent precipitation method. Box Behnken design was used to optimize the process parameters including the Ratio (v/v) of two phases (A), Ulatrasonication time in min (B) and Surfactant concentration (%w/v) (C). A response surface methodology comprising 17 runs was carried out to optimize the nanocrystal formulation of paclitaxel. Two dependent variables particle size and polydispersity index (PDI) were identified as responses. Polynomial equations and response surface curves were used to relate the dependent and independent variables. The optimization model predicted a mean particle size of 147.653 nm and PDI of 0.1706 with A, B and C levels of 5, 15 min and 0.03% w/v respectively. The observed values were in close agreement with the predicted values. The optimized batches of nanocrystals were analyzed by FTIR, DSC and XRPD techniques. The optimized batch revealed irregular morphology as assessed by transmission electron microscopy and was crystalline as determined by thermal analysis and XRPD studies. Paclitaxel nanocrystals exhibited a considerable increase in solubility as well as dissolution rate in comparison with the pure drug. The present work thoroughly explored the influence of process parameters on the physicochemical characteristics of the produced drug nanocrystals.

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