Preparation of Cr2O3 Nanoparticles via Hydrothermal Reduction of CH3OH

2012 ◽  
Vol 463-464 ◽  
pp. 760-763
Author(s):  
Zhen Zhao Pei ◽  
Hong Bin Xu ◽  
Yi Zhang
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Average Particle Size ◽  
Average Particle ◽  
Calcination Temperatures ◽  
Cr2o3 Nanoparticles ◽  
Average Size ◽  
Hydrothermal Reduction ◽  
Scanning Electron

Nanoparticles of Cr2O3 were successfully obtained via hydrothermal reduction of CH3OH. The oxidant and chromium source was CrO3. The process needs no stirrer or surfactant and the CrO3 concentration was 0.83mol/L. The obtained products were loosely agglomerated Cr2O3 nanoparticles with the average size of 29 to 79 nm. Influences of reactant ratios and calcination temperatures on the specific surface area and average particle size were discussed. And the morphology of nanoparticles was investigated by use of field-emission scanning electron microscope.

scholarly journals Preparation of ultrafine iron phosphate micro-powder from phosphate slag

2018 ◽  
Vol 238 ◽  
pp. 02002
Author(s):  
Fangjing Sun ◽  
Yi Zhang ◽  
Jiawei Zhang ◽  
Xixi Yan ◽  
Xiaoyu Liu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Electron Microscope ◽  
Average Particle Size ◽  
Iron Phosphate ◽  
Average Particle ◽  
X Ray ◽  
Particle Size Analyzer ◽  
Phosphate Slag ◽  
Scanning Electron

In this experiment, ultrafine iron phosphate micro-powder was prepared by hydrothermal method which used phosphate slag as an iron source. The effects of reaction temperature, surfactants type and amount on its particle size were explored. The samples were characterized by using Malvern Laser Particle Size Analyzer (MS2000), X-Ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX).The results showed that at 160 °C, 1 wt%CTAB, monoclinic iron phosphate micro-powder was obtained with an average particle size about 0.4 μm which also has a good dispersion in aqueous solution.

Geopolymer Microstructure and Hydration Mechanism of Alkali-Activated Fly Ash-Based Geopolymer

2011 ◽  
Vol 374-377 ◽  
pp. 1481-1484 ◽  
Author(s):  
Yao Jun Zhang ◽  
Hai Hong Li ◽  
Ya Chao Wang ◽  
De Long Xu
Keyword(s):  
Electron Microscope ◽  
Fly Ash ◽  
Scanning Electron Microscope ◽  
Average Particle Size ◽  
Three Dimensional ◽  
Alkaline Condition ◽  
Average Particle ◽  
Hydration Mechanism ◽  
Alkali Activated ◽  
Scanning Electron

The microstructure and hydration mechanism of alkali-activated fly ash-based geopolymer were studied by means of scanning electron microscope (SEM) coupled with energy dispersive X-ray analysis (EDXA) and field emission scanning electron microscope (FESEM). The FESEM photomicrographs indicted that the fly ash-based geopolymer showed three dimensional frameworks with an average particle size of 50 nm. EDXA results demonstrated that the Na-PSS type geopolymer was produced via the disintegration of Si-O-Al and Si-O-Si chemical bonds and the polycondensation reaction between [SiO4]4-and [AlO4]5- tetrahedrons in spherical fly ash particles under alkaline condition.

Control of the Crystal Morphological Characteristic and Size of Nano-PCC via Turbo-Mixing Reactive Precipitation

2015 ◽  
Vol 754-755 ◽  
pp. 770-774
Author(s):  
Mohd Darus Daud ◽  
Aimi Noorliyana Hashim ◽  
Azmi Rahmat ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Ahmad Hadzrul Iqwan Jalauddin
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Rotation Speed ◽  
Average Particle Size ◽  
Average Particle ◽  
Particle Sizes ◽  
Mixing Conditions ◽  
Precipitated Calcium Carbonate ◽  
Novel Technology ◽  
Scanning Electron

An innovative and novel technology method of processing called Turbo-Mixing Reactive Precipitation (TMRP) design proposed as an alternative to this current processing or conventional productions of fine precipitated calcium carbonate (nanoPCC) in turbo-mixing conditions. In this paper, the effect of the stirring rate onto morphology, particle sizes and reaction time of the precipitated CaCO3 particles was discussed. CaCO3 nanoparticles with an average particle size of approximately 15.75 nm were successfully obtained by stirring rotation speed at 900 rpm. The structural analysis was conducted using a Scanning Electron Microscope (SEM) and a Field Emission Scanning Electron Microscope (FESEM). The results showed that the increasing of the multiple’s impeller stirring rotation speed is in favor of the formation of the spherical vaterite.

Synthesis and Nondestructive Characterization of Cr2O3 Nanoparticles-PVA Suspensions

2009 ◽  
Vol 67 ◽  
pp. 259-264
Author(s):  
D.K. Singh ◽  
R.R. Yadav ◽  
D.K. Pandey
Keyword(s):  
Particle Size ◽  
Ultrasonic Velocity ◽  
Average Particle Size ◽  
Reaction System ◽  
Thermal Conditions ◽  
Average Particle ◽  
Calcination Temperatures ◽  
Cr2o3 Nanoparticles ◽  
Nondestructive Characterization

Nanoparticles of chromic oxide (Cr2O3) are widely used in many fields serving as catalysts, wear resistance materials, and advanced colorants. By the reaction system of CrO3 and PVA in aqueous solution, Cr2O3 nanoparticles were prepared via hydrothermal synthesis. We have taken sucrose as reducing agent. The products were loosely agglomerated Cr2O3 particles of 30-80 nm in average particle size calculated from Scherrer’s formula, whose microstructure and the precursor were investigated by SEM. The findings showed that the higher calcination temperatures result in the larger average particle size. Ultrasonic velocity measurements in Cr2O3 nanoparticles suspended in PVA solution were made at different thermal conditions. In the sample Cr2O3+PVA the ultrasonic velocity increases up to 500C and then remains constant. The effort has been made to correlate the ultrasonic velocity/absorption behavior with the magnetic property.

scholarly journals Preparation of Polyetherimide Nanoparticles by a Droplet Evaporation-Assisted Thermally Induced Phase-Separation Method

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1548
Author(s):  
Peng Zhu ◽  
Huapeng Zhang ◽  
Hongwei Lu
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Phase Separation ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Droplet Evaporation ◽  
Average Particle ◽  
Thermally Induced Phase Separation ◽  
Thermally Induced ◽  
Pei Nanoparticles

The droplet evaporation effect on the preparation of polyetherimide (PEI) nanoparticles by thermally induced phase separation (TIPS) was studied. PEI nanoparticles were prepared in two routes. In route I, the droplet evaporation process was carried out after TIPS. In route II, the droplet evaporation and TIPS processes were carried out simultaneously. The surface tension and shape parameters of samples were measured via a drop shape analyzer. The Z-average particle diameter of PEI nanoparticles in the PEI/dimethyl sulfoxide solution (DMSO) suspension at different time points was tested by dynamic light scattering, the data from which was used to determine the TIPS time of the PEI/DMSO solution. The natural properties of the products from both routes were studied by optical microscope, scanning electron microscope and transmission electron microscope. The results show that PEI nanoparticles prepared from route II are much smaller and more uniform than that prepared from route I. Circulation flows in the droplet evaporation were indirectly proved to suppress the growth of particles. At 30 °C, PEI solid nanoparticles with 193 nm average particle size, good uniformity, good separation and good roundness were obtained. Route I is less sensitive to temperature than route II. Samples in route I were still the accumulations of micro and nanoparticles until 40 °C instead of 30 °C in route II, although the particle size distribution was not uniform. In addition, a film structure would appear instead of particles when the evaporation temperature exceeds a certain value in both routes. This work will contribute to the preparation of polymer nanoparticles with small and uniform particle size by TIPS process from preformed polymers.

Effect of Kaolin Particle Size Towards Preparation of Kaolin Ceramic Membrane

2021 ◽  
Vol 02 (01) ◽  
Author(s):  
Siti Khadijah Hubadillah ◽  
◽  
Norsiah Hami ◽  
Nurul Azita Salleh ◽  
Mohd Riduan Jamalludin ◽  
...  
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Preliminary Data ◽  
Membrane Structure ◽  
Ceramic Membrane ◽  
Low Cost ◽  
Dense Structure ◽  
Scanning Electron

The purpose of this work is to study the effect of kaolin particle size for the preparation of low cost ceramic membrane suspension and ceramic membrane structure. Kaolin particle size is categorized into two categories; i) ≤ 1µm and ii) ≥ 1 µm. The suspension is prepared via stirring technique under 1000 rpm at 60°C. The particle size of kaolin is characterized using field emission scanning electron microscope (FESEM) and the prepared suspension is characterized in term of its viscosity. Results indicate that the particle size gave significant effect to the viscosity of ceramic membrane suspension. Preliminary data showed that kaolin with particle size ≤ 1µm resulted ceramic membrane with dense structure.

scholarly journals Effect of the polymeric coating over Fe3O4 particles used for magnetic separation

2010 ◽  
Vol 8 (5) ◽  
pp. 1041-1046 ◽  
Author(s):  
Raúl Reza ◽  
Carlos Martínez Pérez ◽  
Claudia Rodríguez González ◽  
Humberto Romero ◽  
Perla García Casillas
Keyword(s):  
Particle Size ◽  
Magnetite Nanoparticles ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Polymeric Coating ◽  
Average Particle ◽  
Synthesis Conditions ◽  
Aging Conditions ◽  
Magnetite Particles ◽  
Average Size

AbstractIn this work, the synthesis of magnetite nanoparticles by two variant chemical coprecipitation methods that involve reflux and aging conditions was investigated. The influence of the synthesis conditions on particle size, morphology, magnetic properties and protein adsorption were studied. The synthesized magnetite nanoparticles showed a spherical shape with an average particle size directly influenced by the synthesis technique. Particles of average size 27 nm and 200 nm were obtained. When the coprecipitation method was used without reflux and aging, the smallest particles were obtained. Magnetite nanoparticles obtained from both methods exhibited a superparamagnetic behavior and their saturation magnetization was particle size dependent. Values of 67 and 78 emu g−1 were obtained for the 27 nm and 200 nm magnetite particles, respectively. The nanoparticles were coated with silica, aminosilane, and silica-aminosilane shell. The influence of the coating on protein absorption was studied using Bovine Serum Albumin (BSA) protein.

Exploring the Parameter Space of Point Spread Function Determination for the Scanning Electron Microscope—Part II: Effect on Image Restoration Quality

2019 ◽  
Vol 25 (05) ◽  
pp. 1183-1194
Author(s):  
Mandy C. Nevins ◽  
Richard K. Hailstone ◽  
Eric Lifshin
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Image Quality ◽  
Scanning Electron Microscope ◽  
Image Restoration ◽  
Point Spread Function ◽  
Background Correction ◽  
Point Spread ◽  
Spread Function ◽  
Scanning Electron

AbstractPoint spread function (PSF) deconvolution is an attractive software-based technique for resolution improvement in the scanning electron microscope (SEM) because it can restore information which has been blurred by challenging operating conditions. In Part 1, we studied a modern PSF determination method for SEM and explored how various parameters affected the method's ability to accurately estimate the PSF. In Part 2, we extend this exploration to PSF deconvolution for image restoration. The parameters include reference particle size, PSF smoothing (K), background correction, and restoration denoising (λ). Image quality was assessed by visual inspection and Fourier analysis. Overall, PSF deconvolution improved image quality. Low λ enhanced image sharpness at the cost of noise, while high λ created smoother restorations with less detail. λ should be chosen to balance feature preservation and denoising based on the application. Reference particle size within ±0.9 nm and K within a reasonable range had little effect on restoration quality. Restorations using background-corrected PSFs had superior quality compared with using no background correction, but if the correction was too high, the PSF was cut off causing blurrier restorations. Future efforts to automatically determine parameters would remove user guesswork, improve this method's consistency, and maximize interpretability of outputs.

Automation of size fractionation to extract clays and silts

Clay Minerals ◽  
2011 ◽  
Vol 46 (3) ◽  
pp. 515-523 ◽  
Author(s):  
Youjun Deng ◽  
M. G. Tenorio Arvide
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Laser Diffraction ◽  
Size Fractionation ◽  
Microscope Examination ◽  
Household Appliance ◽  
Lawn Irrigation ◽  
Sedimentation Time ◽  
Scanning Electron

AbstractThe objective of this study was to build an automated size fractionator to process up to 16 samples at one time. Most parts used in the apparatus are inexpensive items, available from lawn irrigation, household appliance and aquatic pet supply stores. The device can be used to extract different silt and clay fractions by changing sedimentation time. A bentonite, a kaolin and an ironoxide-rich Oxisol were fractionated by this instrument to sequentially extract particles that have sizes equivalent to <2 µm, <5 µm, <10 µm and <20 µm quartz spheres. A laser diffraction particle size analyser revealed size differences in the different fractions and also showed that the silt fractions contained particles having slightly larger sizes than the assumed diameters of spherical quartz. Scanning electron microscope examination suggested that the greater particle size was mainly due to the non-spherical shapes of the particles and a reduced bulk density of the porous aggregates.

Effect of Different Abrasives on Chemical Mechanical Polishing for Magnesia Alumina Spinel

2020 ◽  
Vol 866 ◽  
pp. 115-124
Author(s):  
Zhan Kui Wang ◽  
Ming Hua Pang ◽  
Jian Xiu Su ◽  
Jian Guo Yao
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Chemical Mechanical Polishing ◽  
Removal Rate ◽  
Mechanical Polishing ◽  
Key Factors ◽  
Particle Size Analyzer ◽  
Scanning Electron ◽  
Shape And Size

In this paper, a series of chemical mechanical polishing (CMP) experiments for magnesia alumina (Mg-Al) spinel were carried out with different abrasives, and the materials removal rate (MRR) and surface quality was evaluated to explore their different effects. The scanning electron microscope (SEM) and laser particle size analyzer were also employed to test the micro-shape and size distribution of abrasives. Then, the mechanism of different effects with different abrasives was analyzed in CMP for Mg-Al spinel. Those experimental results suggest that different subjecting pressure ratios of abrasives to polishing pad with different abrasive are the key factors leading to difference polishing performances in CMP.

Sign in / Sign up

Export Citation Format

Share Document