A New Process for Preparing Nanosize Ceramic Powders

1994 ◽  
Vol 351 ◽  
Author(s):  
Yong S. Zhen ◽  
Kenneth E. Hrdina ◽  
Robert J. Remick
Keyword(s):  
Particle Size ◽  
Metal Oxides ◽  
Average Particle Size ◽  
Cost Effective ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Mixed Metal Oxides ◽  
Ceramic Powders ◽  
New Process ◽  
The Cost

ABSTRACTWe have developed a new poly-foam process for the cost effective preparation of ceramic nanoparticles. The process utilizes the chemistry of polyurethane reactions and is proven to be effective for forming nanometer size ceramic powders of a great variety of single metal oxides and mixed metal oxides. In general, ceramic powders can be prepared by this process having a range of average particle size between 3 to 50 nm, with very narrow particle size distribution. They are free of hard agglomerates, are chemically pure and uniform, and are essentially spherical in shape.

Fabrication and Microstructure of ZnO-TiO2 Composite Membranes by a Reverse Micelle and Sol-Gel Processing

2006 ◽  
Vol 510-511 ◽  
pp. 786-789 ◽  
Author(s):  
Dong Sik Bae ◽  
Byung Ik Kim ◽  
Kyong Sop Han
Keyword(s):  
Particle Size ◽  
Reverse Micelle ◽  
Porous Alumina ◽  
Sol Gel ◽  
Average Particle Size ◽  
Composite Membranes ◽  
Dip Coating ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Alumina Support

ZnO-TiO2 nanoparticles were synthesized by a reverse micelle and sol-gel process. The average particle size of the colloid was below 30 nm and well dispersed in the solution. ZnOTiO2 composite membranes were fabricated by using the dip-coating method on a porous alumina support. ZnO-TiO2 composite membranes showed a crack-free microstructure and narrow particle size distribution even after the heat treatment up to 600°C. The average particle size of the membrane was 30-40nm, and the pore size of ZnO-TiO2 composite membrane was below 10 nm.

Synthesis of Nanostructured Magnetic Mixed-Oxide Ferrite Powders by Using A Novel Chemical Method

2002 ◽  
Vol 720 ◽  
Author(s):  
N N Ghosh
Keyword(s):  
Particle Size ◽  
Mixed Oxide ◽  
Chemical Method ◽  
Average Particle Size ◽  
Cost Effective ◽  
Water Soluble ◽  
Average Particle ◽  
Chemical Route ◽  
Water Soluble Polymer ◽  
Different Temperatures

AbstractIn the present investigation, an attempt has been made to establish a new chemical route for synthesis of the nanostructured mixed oxide ferrite powders. By using this chemical method a variety of ferrite powders having spinel structure and doped with Co, Ni, Mn, Zn etc has been prepared. In this method nitrate salts of the different metals were used as starting materials. The aqueous solutions of the metal nitrates were mixed according to the molar ration of the compositions. Then the mixtures were mixed with an aqueous solution of water soluble polymer (polyvinyl alcohol). This mixture after drying yield fluffy brown powders. These powders were then calcined at different temperatures ranging from 400 °C to 700 °C. Nanostructured powders were obtained from the thermal decomposition of the brown powders. The powders, prepared by calcinations at different temperatures, were characterized by using X-Ray diffraction analysis, IR spectroscopy, TGA/DTA, and TEM. It was observed that the average particle size of the powders are in nanometer scale with a narrow size distribution. The average particle size of the powders was increased with the increase of calcinations temperature.This chemical method has proved to provide a convenient process for the preparation of nanostructured ceramic powders at comparatively low temperatures and offers the potential of being a simple and cost-effective route.

scholarly journals Application of surfactants for the synthesis of qualitative hydroxide and metallic cobalt nanopowders

2021 ◽  
pp. 4-11
Author(s):  
Van Minh Nguyen ◽  
Tien Hiep Nguyen ◽  
Stanislav V. Gorobinsky
Keyword(s):  
Particle Size ◽  
Hydrogen Reduction ◽  
Cetylpyridinium Chloride ◽  
Average Particle Size ◽  
Sodium Dodecyl ◽  
Chemical Precipitation ◽  
Spherical Particles ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Application Of Surfactants

In this work, nanopowders (NP) Co(OH)2 were obtained by chemical precipitation from aqueous solutions of cobalt nitrate Co(NO3)2 and alkali NaOH (10 wt. %) using surfactants: sodium dodecyl sulfate (SDS) and cetylpyridinium chloride (CPC) (0.1 wt. %). It was shown that Co(OH)2 NP with 0.1% SDS is the best quality product, since its dispersion increases more than 2 times compared to the samples with 0.1% CPC and without surfactants. In this case, the Co(OH)2 NP has the form of flakes with an irregular shape and a nanometer size (about 100 nm) with an average thickness of 30 nm. It was found that the average particle size of Co NP obtained by hydrogen reduction of Co(OH)2 NP with 0.1% SDS at 280°C has a maximum on the distribution histogram shifted to the interval 41–50 nm, which is characterized by a narrow particle size distribution and represents spherical particles sintered with each other.

scholarly journals Growth of significantly low dimensional zinc orthotitanate (Zn2TiO4) nanoparticles by solid state reaction method

2018 ◽  
Vol 50 (1) ◽  
pp. 133-138 ◽  
Author(s):  
Lizina Khatua ◽  
Rudrashish Panda ◽  
Avanendra Singh ◽  
Arpan Nayak ◽  
Pravakar Satapathy ◽  
...  
Keyword(s):  
Particle Size ◽  
Solid State ◽  
Surface Area ◽  
Solid State Reaction ◽  
Average Particle Size ◽  
Cost Effective ◽  
Solid State Reaction Method ◽  
Average Particle ◽  
Reaction Method ◽  
Low Dimensional

In this work, the ZnO-TiO2 mixed phase nanoparticles were prepared by solid state reaction method by using ZnO and TiO2 powder as precursors. The X-ray diffraction pattern shows a dominant phase of Zinc Orthotitanate (Zn2TiO4). The average particle size (58?18 nm) calculated by the analysing FESEM data closely matches with the particle size calculated by Scherrer?s equation. The calculated average particle size is significantly smaller than the previously published results of nanoparticles, prepared by same method. In the Brunauer-Emmett-Teller (BET) study the specific surface area of the nanoparticles was found as 8.78 m2/g which is similar to the surface area reported in this material prepared by mechanochemical method. The method which we report is simpler and cost effective unlike the previous reported.

scholarly journals Structural and Optical Properties of Silicon Carbide Powders Synthesized from Organosilane Using High-Temperature High-Pressure Method

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3111
Author(s):  
Evgeny A. Ekimov ◽  
Vladimir S. Krivobok ◽  
Mikhail V. Kondrin ◽  
Dmitry A. Litvinov ◽  
Ludmila N. Grigoreva ◽  
...  
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Average Particle Size ◽  
Synthesis Temperature ◽  
Narrow Particle Size Distribution ◽  
High Tech ◽  
Average Particle ◽  
Coupled Modes ◽  
Dominant Type ◽  
High Structure

The development of new strategies for the mass synthesis of SiC nanocrystals with high structure perfection and narrow particle size distribution remains in demand for high-tech applications. In this work, the size-controllable synthesis of the SiC 3C polytype, free of sp2 carbon, with high structure quality nanocrystals, was realized for the first time by the pyrolysis of organosilane C12H36Si6 at 8 GPa and temperatures up to 2000 °C. It is shown that the average particle size can be monotonically changed from ~2 nm to ~500 nm by increasing the synthesis temperature from 800 °C to 1400 °C. At higher temperatures, further enlargement of the crystals is impeded, which is consistent with the recrystallization mechanism driven by a decrease in the surface energy of the particles. The optical properties investigated by IR transmission spectroscopy, Raman scattering, and low-temperature photoluminescence provided information about the concentration and distribution of carriers in nanoparticles, as well as the dominant type of internal point defects. It is shown that changing the growth modes in combination with heat treatment enables control over not only the average crystal size, but also the LO phonon—plasmon coupled modes in the crystals, which is of interest for applications related to IR photonics.

scholarly journals Electrophysical properties of composites based on epoxy resin and carbon fillers

2021 ◽  
Vol 12 (2) ◽  
pp. 104-111
Author(s):  
O. G. Sirenko ◽  
◽  
O. M. Lisova ◽  
S. M. Makhno ◽  
G. M. Gunya ◽  
...  
Keyword(s):  
Particle Size ◽  
Epoxy Resin ◽  
Size Distribution ◽  
Average Particle Size ◽  
Construction Materials ◽  
Expanded Graphite ◽  
Cost Effective ◽  
Average Particle ◽  
Carbon Filler ◽  
Carbon Fillers

Polymeric construction materials based on epoxy resin, carbon fillers, such as graphene nanoplates (GNP), carbon nanotubes (CNT) and fillers of inorganic nature – perlite, vermiculite, sand with improved electrophysical characteristics have been developed. The electrophysical propertieгs of composites obtained in various ways which differ according to the principle of injecting components have been investigated. GNP were obtained in two ways. Size distribution of GNP obtained by electrochemical method is 50 to 150 nm. The average particle size is up to 100 nm. It occurs that these particles tend to aggregate as it is shown by the method of dynamic light scattering. The GNP obtained by dispersing thermally expanded graphite in water in a rotary homogenizer have a particle size distribution of 400 to 800 nm if very small particles and large aggregates are absent. The second method of obtaining GNP is less energy consuming and requires fewer manufacturing cycles, so it is more cost-effective. Obtaining composites using aqueous suspensions of GNP is environmentally friendly. Due to the hydrophobic properties of its surface the electrical conductivity of the system which uses vermiculite is higher than one of that which uses perlite for composites with CNT and GNP. It has been found that the difference of electrophysical characteristics between two systems which contain the same amount of carbon filler is caused by the nature of the surface of dielectric components – sand. By changing the content of dielectric ingredients can expand the functionality of composites if use them for shielding from electromagnetic fields.

scholarly journals Effect of dopants [Gd3+, Sm3+, Ca2+, Sr2+ and Ba2+] on the performance characteristics of ceria based electrolytes for application in solid oxide fuel cells

2014 ◽  
Vol 10 (2) ◽  
Author(s):  
M.L. Reni ◽  
A. Samson Nesaraj
Keyword(s):  
Particle Size ◽  
Fuel Cells ◽  
Low Temperature ◽  
Solid Oxide Fuel Cells ◽  
Average Particle Size ◽  
Solid Oxide ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Doped Ceria ◽  
Oxide Fuel

Doped CeO2 based materials are now-a-days proposed as alternate electrolyte materials for solid oxide fuel cells (SOFCs) working at low temperature (~723 – 873 K). In this research work, nanoparticles of CeO2 doped with Gd3+, Sm3+, Ca2+, Sr2+ and Ba2+were prepared by a simple homogeneous chemical precipitation method. The prepared materials (after heat treatment at 1023 K for 2 hours) were systematically characterized by XRD, EDAX analysis, FTIR , particle size analysis and SEM.  Lattice parameters were calculated from the XRD data. The XRD results indicate that all the doped ceria samples studied are single phase with a cubic fluorite structure. The average particle size of the doped ceria powder was about 48 – 115 nm and the particles have shown narrow particle size distribution patterns. AC impedance spectroscopy studies performed on the sintered specimens have shown better oxide ion conductivity values and hence these materials may be suitable for application as electrolyte materials in solid oxide fuel cells working at low temperature (~723 – 873 K). ________________________________________GRAPHICAL ABSTRACT

scholarly journals β-hexanitrohexaazaisowurtzitane Particles Prepared by Spray Drying and its Characterization

2021 ◽  
Vol 27 (1) ◽  
pp. 119-124
Author(s):  
Wenzheng XU ◽  
Hao LI ◽  
Xin LIANG ◽  
Jie WANG ◽  
Jinyu PENG ◽  
...  
Keyword(s):  
Particle Size ◽  
Spray Drying ◽  
Ultrafine Particles ◽  
Average Particle Size ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Thermal Stimulus ◽  
Particle Size Analyzer ◽  
Xrd Patterns ◽  
The Impact

In this paper, the ultrafine β-hexanitrohexaazaisowurtzitane (β – CL – 20) particles were prepared by spray drying method. The CL – 20 samples were characterized by scanning electron microscope (SEM), particle size analyzer, X-ray diffraction (XRD), and Differential Scanning Calorimeter (DSC). Furthermore, the safety properties of samples under impact and thermal stimulus were tested and analyzed. The results of SEM showed that the average particle size of ultrafine CL – 20 particles with a narrow particle size distribution, were about 320 nm, and the shape was elliptical. The XRD patterns indicated that the polymorphic phase of ultrafine particles was mainly β-type. Compared with that of raw CL – 20, the impact sensitivity of the ultrafine CL – 20 had been decreased significantly, for the drop height (H50) was increased from 13.0 to 33.5 cm. The critical explosion temperature of the ultrafine CL – 20 decreased from 232.16 ℃ to 227.93 ℃, indicating that the thermal stability of the ultrafine CL – 20 is lower than that of raw CL – 20.

Finishing of Silk Textile with Fluorinated Polyacrylate Latex and the Effect of Silicone Cross-Linking Bond in Copolymer on Hydrophobicity and Lipophobicity

2013 ◽  
Vol 796 ◽  
pp. 360-363 ◽  
Author(s):  
Liang Shan ◽  
Zhan Xiong Li ◽  
Yan Xu ◽  
Lu Cai ◽  
Xiong Zang ◽  
...  
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Narrow Particle Size Distribution ◽  
Cross Linking ◽  
Average Particle ◽  
Silk Fabric ◽  
Emulsion Copolymerization ◽  
Fluorinated Polyacrylate ◽  
Level 3 ◽  
Textile Finishing

The lightly cross-linked fluorinated polyacrylate latex was synthesized by emulsion copolymerization, in which fluorine containing acrylate, butyl acrylate (BA) and organosiloxane containing bisacrylate were used as monomers. The fluorine containing co-polymeric emulsion was obtained with narrow particle size distribution and the average particle size to be about 130 nm. The emulsion with and without addition of cross-linking agent was applied on silk textile finishing. The result shows that, treating with the emulsion without cross-linking agent, the water-and oil-repellency of silk fabric reached level 3-4 and level 3, respectively, and the contact angle was up to 133.5°. After addition of cross-linking agent, the emulsion can afford the silk fabric with better water-and oil-repellency of level 4 and level 3-4, respectively. The improvement of water-and oil-repellency can probably be attributed to the lightly cross-linking structure of fluoropolymer, the latter resulted in more dense film on the surface of silk fabric after finishing.

scholarly journals Comparative Study of Different Crystallization Methods in the Case of Cilostazol Crystal Habit Optimization

Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 295 ◽  
Author(s):  
Tímea Tari ◽  
Piroska Szabó-Révész ◽  
Zoltán Aigner
Keyword(s):  
Particle Size ◽  
Dissolution Rate ◽  
Mixing Time ◽  
Average Particle Size ◽  
Aqueous Solubility ◽  
Impinging Jet ◽  
Polymorphic Form ◽  
Crystal Habit ◽  
Narrow Particle Size Distribution ◽  
Average Particle

The therapeutic usage of cilostazol is limited owing to its poor aqueous solubility and oral bioavailability. Our aim was to produce cilostazol crystals with small average particle size; besides suitable roundness, narrow particle size distribution and stable polymorphic form to increase its dissolution rate and improve processability. Different conventional crystallization methods with or without sonication were compared with impinging jet crystallization combined with cooling, and the optimization of the various parameters was also implemented. The effects of post-mixing time and temperature difference were studied by means of a full factorial design. The physical properties of powder particles were characterized by, i.a., XRPD, DSC and SEM. The dissolution rate and the contact angle of solid surfaces were also determined to elucidate the relationship between wettability and dissolution. It was observed that impinging jet crystallization combined with cooling is a very effective and reproducible method for reducing the particle size of cilostazol. This method resulted in significantly smaller particle size (d(0.5) = 3–5 μm) and more uniform crystals compared to the original ground material (d(0.5) = 24 μm) or the conventional methods (d(0.5) = 8–14 μm), and it also resulted in a stable polymorphic form and enhanced the dissolution rate.

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