The Effect of Particle Sizes on the Concentration Dependence of the Surface Tension of Aqueous Suspensions of Bentonite

2021 ◽  
Vol 1022 ◽  
pp. 212-217
Author(s):  
R.Kh. Dadashev ◽  
R.S. Dzhambulatov ◽  
Z.S. Khasbulatova ◽  
Kh.S. Talkhigova
Keyword(s):  
Surface Tension ◽  
Solid Phase ◽  
Aqueous Suspension ◽  
Average Particle Size ◽  
Average Particle ◽  
Particle Sizes ◽  
Coarse Particles ◽  
Factors Affecting ◽  
Aqueous Suspensions ◽  
Surface Tension Isotherms

The paper presents experimental results on the dependence of surface tension on the concentration of a suspension of bentonite (0 - 10% by weight). The isotherms σ of aqueous suspensions of bentonite are characterized by local minima in the concentration range of 3-4 mass% of the solid phase. It has been established that a decrease in the average particle size leads to the disappearance of the extremum on the surface tension isotherms. The data obtained led to the conclusion that the most important factors affecting the nature of the isotherms of the surface tension of bentonite suspensions are the degree of dispersion and the presence in the aqueous suspension of bentonite, both colloidal and coarse particles.

scholarly journals Polymer Binders of Ceramic Nanoparticles for Precision Casting of Nickel-Based Superalloys

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1714
Author(s):  
Paweł Wiśniewski
Keyword(s):  
Solid Phase ◽  
Average Particle Size ◽  
Water Soluble ◽  
Ethyl Silicate ◽  
Average Particle ◽  
Precision Casting ◽  
Polymer Binders ◽  
Initial Stage ◽  
Nano Alumina ◽  
Solid Phase Content

This study presents the general characteristics of binders used in precision casting of Nickel-based superalloys. Three groups of binders were described: resins, organic compounds, and materials containing nanoparticles in alcohol or aqueous systems. This study also includes literature reports on materials commonly used and those recently replaced by water-soluble binders, i.e., ethyl silicate (ES) and hydrolysed ethyl silicate (HES). The appearance of new and interesting solutions containing nano-alumina is described, as well as other solutions at the initial stage of scientific research, such as those containing biopolymers, biodegradable polycaprolactone (PCL), or modified starch. Special attention is paid to four binders containing nano-SiO2 intended for the first layers (Ludox AM, Ludox SK) and structural layers (EHT, Remasol) of shell moulds. Their morphology, viscosity, density, reactions, and electrokinetic potential were investigated. The binders were characterized by a high solid-phase content (>28%), viscosity, and density close to that of water (1–2 mPa·s) and good electrokinetic stability. The nanoparticles contained in the binders were approximately spherically shaped with an average particle size of 16–25 nm.

scholarly journals Influence of Cu on the Improvement of Magnetic Properties and Structure of L10 FePt Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1097
Author(s):  
Luran Zhang ◽  
Xinchen Du ◽  
Hongjie Lu ◽  
Dandan Gao ◽  
Huan Liu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Annealing Temperature ◽  
Reduction Method ◽  
Solid Phase ◽  
Average Particle Size ◽  
Fept Nanoparticles ◽  
Average Particle ◽  
Phase Reduction ◽  
Different Temperatures ◽  
One Step

L10 ordered FePt and FePtCu nanoparticles (NPs) with a good dispersion were successfully fabricated by a simple, green, one-step solid-phase reduction method. Fe (acac)3, Pt (acac)2, and CuO as the precursors were dispersed in NaCl and annealed at different temperatures with an H2-containing atmosphere. As the annealing temperature increased, the chemical order parameter (S), average particle size (D), coercivity (Hc), and saturation magnetization (Ms) of FePt and FePtCu NPs increased and the size distribution range of the particles became wider. The ordered degree, D, Hc, and Ms of FePt NPs were greatly improved by adding 5% Cu. The highest S, D, Hc, and Ms were obtained when FePtCu NPs annealed at 750 °C, which were 0.91, 4.87 nm, 12,200 Oe, and 23.38 emu/g, respectively. The structure and magnetic properties of FePt and FePtCu NPs at different annealing temperatures were investigated and the formation mechanism of FePt and FePtCu NPs were discussed in detail.

scholarly journals Surface Activity of Humic Acid and Its Sub-Fractions from Forest Soil

2021 ◽  
Vol 13 (15) ◽  
pp. 8122
Author(s):  
Shijie Tian ◽  
Weiqiang Tan ◽  
Xinyuan Wang ◽  
Tingting Li ◽  
Fanhao Song ◽  
...  
Keyword(s):  
Surface Tension ◽  
Particle Size ◽  
Humic Acid ◽  
Forest Soil ◽  
Surface Activity ◽  
Self Assembly ◽  
Average Particle Size ◽  
Gaussian Model ◽  
Exponential Model ◽  
Average Particle

Surface activity of humic acid (HA) and its six sub-fractions isolated from forest soil were characterized by surface tension measurements, dynamic light scattering, and laser doppler electrophoresis. The surface tension of HA and its sub-fractions reduced from 72.4 mN·m−1 to 36.8 mN·m−1 in exponential model with the increasing concentration from 0 to 2000 mg·L−1. The critical micelle concentration (CMC) and Z-average particle size ranged from 216–1024 mg·L−1 and 108.2–186.9 nm for HA and its sub-fractions, respectively. The CMC have related with alkyl C, O-alkyl C, aromatic C, and carbonyl C (p < 0.05), respectively, and could be predicted with the multiple linear regression equation of CMC, CMC = 18896 − 6.9 × C-296 × alkyl C-331 × aromatic C-17019 × H/C + 4054 × HB/HI (p < 0.05). The maximum particle size was 5000 nm after filtered by a membrane with pore size of 450 nm, indicating HA and its sub-fractions could progressed self-assembly at pH 6.86. The aggregate sizes of number-base particle size distributions were mainly in six clusters including 2 ± 1 nm, 5 ± 2 nm, 10 ± 3 nm, 21 ± 8 nm, 40 ± 10 nm, and >50 nm analyzed by Gaussian model that maybe due to the inconsistency of the components and structures of the HA sub-fractions, requiring further study. It is significance to explore the surface activity of HA and its sub-fractions, which is helpful to clarify the environmental behavior of HA.

scholarly journals HOMOGENIZATION OF PARTICLE SIZES IN LaTiO2N OXYNITRIDE PIGMENTS BY BEAD-MILLING TECHNIQUE

2012 ◽  
Vol 06 ◽  
pp. 215-220 ◽  
Author(s):  
KAORU SHINNOU ◽  
HIRONORI FUJITO ◽  
TOMOOKI KAWASAKI ◽  
HIDEHITO ANDO ◽  
MAIKO MITO ◽  
...  
Keyword(s):  
Ball Milling ◽  
Absorption Edge ◽  
Aqueous Suspension ◽  
Wavelength Region ◽  
Average Particle ◽  
Particle Sizes ◽  
Bead Milling ◽  
Primary Particles ◽  
Diffuse Reflectivity

Diffuse reflectivity in the longer wavelength region after the absorption edge was studied on the LaTiO 2 N nitrided. It was discussed in the viewpoint of particle sizes by use of ball milling and bead milling technique. The diffuse reflectivity after absorption edge of the LaTiO 2 N powders got lower in accordance with the reduction of particle sizes. In case of LaTiO 2 N aqueous suspension after the bead-milling treatment in which the primary particles were well dispersed, remarkable enhancement of the diffuse reflectivity was observed with decreasing the average particle sizes.

scholarly journals Obtaining the conductive SnO2 films by chemical bath deposition method

2019 ◽  
Vol 60 (11) ◽  
pp. 1-10
Author(s):  
Vladislav I. Rogozin ◽  
◽  
Vyacheslav F. Markov ◽  
Larisa N. Maskaeva ◽  
Anastasia E. Krasovskaya ◽  
...  
Keyword(s):  
Tin Dioxide ◽  
Solid Phase ◽  
Average Particle Size ◽  
Ammonium Fluoride ◽  
Contact Layer ◽  
Average Particle ◽  
Solution Ph ◽  
Before And After ◽  
Initial Salt ◽  
Conductive Properties

Thanks to such unique properties as transparency and conductivity tin dioxide often utilize as transparent contact layer to produce displays, solar cells, and sensor devices. Hydrochemical method of deposition SnO2 films is a perspective due to its simplicity, and economical efficiency. The ionic equilibria analysis was carried out and the boundary conditions of Sn(OH)2 solid phase formation in the «Sn2+ – H2O – OH‾» system calculated. It was established, that tin(II) hydroxide may be obtain in the range 2 < pH < 12. Preliminary results allow to determinate an optimal mixture sourness interval 1 < pH < 5. Revealed, that the thickness of the Sn(OH)2 films strongly depends on the solution pH. Maximum value of 488 nm reached at pH = 8. Conductive SnO2 layers were obtained on a glass and sitall substrates with simultaneously presence of antimony chloride and ammonium fluoride followed by annealing in air. The thickness vs temperature and thickness vs tin initial salt concentration dependences were installed. The uniform tin hydroxide layers with a thickness of ~74 nm may be synthesized under pH = 2 conditions. By the electron microscopy method the average particle size was established changing from 200 to 400 nm for as-synthesized films, to ~20 nm for annealed which indicates the nanostructure nature of the films. The morphology, elemental composition and conductive properties of deposited films were investigated before and after heating stage. Studying the annealing temperature influence at the film resistance were identified a three temperature ranges within which the films sharply differ in their conductive properties, which is associated with phase and structural transformations in them. Shown, that the most conductive SnO2 films with the omic resistance 3-5 kOm/sm were obtained at the temperature range 620-870 K.

scholarly journals Stimulating effect of magnesium hydroxide on aqueous characteristics of iron nanocomposites

2019 ◽  
Vol 80 (10) ◽  
pp. 1996-2002 ◽  
Author(s):  
I. Maamoun ◽  
O. Eljamal ◽  
O. Falyouna ◽  
R. Eljamal ◽  
Y. Sugihara
Keyword(s):  
Particle Size ◽  
Magnesium Hydroxide ◽  
Iron Nanoparticles ◽  
Aqueous Suspension ◽  
Average Particle Size ◽  
Degree Of Crystallinity ◽  
Iron Core ◽  
Average Particle ◽  
Size Estimation ◽  
Aqueous Corrosion

Abstract Nanoscale zero-valent iron (nFe0) tends to aggregate, which dramatically affects its aqueous characteristics and thereby its potential in water treatment applications. Hence, the main aim of this study is to overcome such drawback of nFe0 by a new modification approach. Iron nanoparticles were modified by magnesium hydroxide (Mg(OH)2) addition with different mass ratios in order to form a nanocomposite with superior aqueous characteristics. The optimization process of the iron–magnesium nanocomposite (nFe0-Mg) was conducted through different approaches including settlement tests, morphology and crystallinity investigations and particle size estimation. The addition of Mg(OH)2 to nFe0 with a Mg/Fe coating ratio of 100% resulted in stimulated stability of the particles in aqueous suspension with around 95% enhancement in the suspension efficiency compared to that of nFe0. Results showed that the average particle size and degree of crystallinity of nFe0-Mg(Mg/Fe:100%) decreased by 46.7% and increased by 16.8%, respectively, comparing with that of nFe0. Additionally, the iron core of the synthesized nFe0 was adequately protected from aqueous corrosion with lower iron oxides leachates after the optimal modification with Mg(OH)2. Furthermore, Mg(OH)2 coating resulted in a stimulated adsorption reactivity of the composite towards phosphorus (P) with around 3.13% promotion in the removal efficiency comparing to that of nFe0.

Effects of Dissolving Agents on Particle Size Reduction of Titanium Dioxide Synthesized by Solution Combustion Technique

2016 ◽  
Vol 690 ◽  
pp. 236-239
Author(s):  
Oratai Jongprateep ◽  
Rachata Puranasamriddhi
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Sulfuric Acid ◽  
Nitric Acid ◽  
Average Particle Size ◽  
Average Particle ◽  
Particle Sizes ◽  
Solution Combustion ◽  
Initial Reagent ◽  
Combustion Technique

High photocatalytic activity of nanoparticulate titanium dioxide has attracted worldwide attention. Synthesis techniques of the nanoparticles, however, often require high energy supply or costly initial reagents. Solution combustion technique is an energy-effective technique capable of synthesizing nanosized titanium powders. This research aimed at utilizing a less expensive initial reagent in synthesis of nanoparticulate titanium dioxide by the solution combustion technique. The research also examined effects of dissolving agents on chemical composition and particle sizes of the synthesized powders. A low-cost initial reagent, titanium dioxide with average particle size of 154 nanometers, was dissolved in sulfuric acid or dispersed in nitric acid prior to the combustion. Experimental results revealed that the pure anatase phase titanium dioxide was successfully obtained in powders prepared from both sulfuric acid and nitric acid. The average particle size of the powder prepared from sulfuric acid was 77 nanometers, while that of the powder prepared from nitric acid was 117 nanometers. The difference in particle sizes was attributed to solubility of the initial reagent in the acid. Complete solution of initial reagent in sulfuric acid was the main factor attributed to finer particle size.

Experimental Study of Heat Conduction in Aqueous Suspensions of Aluminum Oxide Nanoparticles

2008 ◽  
Vol 130 (9) ◽  
Author(s):  
Y. Sungtaek Ju ◽  
Jichul Kim ◽  
Ming-Tsung Hung
Keyword(s):  
Thermal Conductivity ◽  
Aluminum Oxide ◽  
Average Particle Size ◽  
Oxide Nanoparticles ◽  
Average Particle ◽  
Aluminum Oxide Nanoparticles ◽  
Aqueous Suspensions ◽  
Effective Medium Model ◽  
Transient Hot Wire Technique ◽  
Different Temperatures

We report measurements of the thermal conductivity of aqueous suspensions of aluminum oxide nanoparticles with nominal diameters of 20nm, 30nm, and 45nm and at volume concentrations up to 10%. Potential complications in the pulsed transient hot-wire technique for characterizing nanofluids are examined, which motivate the development of a microhot strip setup with a small thermal time constant. The average particle size is monitored for samples subjected to different durations of sonication and the thermal conductivity is determined at two different temperatures for each of the samples. The present data do not reveal any anomalous enhancement in the thermal conductivity previously reported for comparable nanofluids. The concentration dependence of the thermal conductivity can be explained using the conventional effective medium model with a physically reasonable set of parameters.

Factors Affecting the Stiffening Potential of Mineral Fillers

1998 ◽  
Vol 1638 (1) ◽  
pp. 94-100 ◽  
Author(s):  
Naga Shashidhar ◽  
Pedro Romero
Keyword(s):  
Average Particle Size ◽  
Asphalt Mixture ◽  
Quantitative Relationship ◽  
Packing Fraction ◽  
Complex Problem ◽  
Average Particle ◽  
Factors Affecting ◽  
And Performance ◽  
Two Parameters ◽  
Mineral Fillers

The workability and performance of bituminous mixes is known to be affected by the filler-asphalt mixture (or mastic) properties. The addition of fillers is known to stiffen asphalt. The degree of stiffening is a function of several filler and asphalt properties, which are not well understood. A fundamental approach to understanding the influence of such factors on the stiffening potential of filler in asphalt is discussed. This complex problem is simplified by introducing two intermediate measurable parameters, the maximum packing fraction, ϕ m, and the generalized Einstein coefficient, KE. This enables a better understanding of the influence of various factors such as average particle size, gradation, particle shape, presence of agglomerates, degree of dispersion, and the asphalt-filler interface on the stiffening potential of asphalt. First, the relationship between these two parameters and stiffening is thoroughly examined. The physical meaning of these parameters is discussed. Second, the influence of each factor on stiffening potential is addressed individually, supported by experimental data and relevent literature to derive a quantitative relationship. Finally, the relative advantages of the approach over the traditional treatment are discussed. It is further shown that, since the parameters φm and KE take into account the properties of an asphalt-filler system as a whole, they are likely to predict stiffening more accurately than Rigden’s fractional voids approach which is based on the properties of fillers alone.

Phase Formation, Crystal Structure and Ion Conductivity of Silver Antimonate-Molybdates

2020 ◽  
Vol 20 (7) ◽  
pp. 4597-4600
Author(s):  
Yu. A. Lupitskaya ◽  
D. A. Kalganov ◽  
L. Yu. Kovalenko ◽  
F. A. Yaroshenko
Keyword(s):  
Solid Phase ◽  
Rietveld Method ◽  
Structural Parameters ◽  
Average Particle Size ◽  
Structural Disorder ◽  
Synthesis Temperature ◽  
Average Particle ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Pyrochlore Type

The features of the formation of compounds based on silver antimonate obtained in the AgNO3–Sb2O3–MoO3 system by the solid-phase reaction were investigated. For a synthesis temperature of 1023 K, a homogeneous concentration region of the Ag2−xSb2−xMoxO6 solid solution with a structure of the defective pyrochlore type in the range of 0.0 ≤ x ≤ 2.0 was detected. The Rietveld method, within the constraints of the Fd-3m space group, was used to refinement of X-ray diffraction data, specify the structural parameters of powders, and the correlation of structural disorder with their electrically conductive properties. Relative density and average particle size for ceramic samples sintered at 1223 K were determined using scanning electron microscopy.

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