scholarly journals Determination of properties of non-spherical VT20 alloy powders for modelling packing density

2020 ◽  
Vol 96 (4) ◽  
pp. 56-63
Author(s):  
Z.A. Duriagina ◽  
◽  
I.A. Lemishka ◽  
V.V. Kulyk ◽  
H.A. Hrydova ◽  
...  
Keyword(s):  
Particle Size ◽  
Titanium Alloy ◽  
Packing Density ◽  
Alloy Powder ◽  
Fractional Composition ◽  
Spherical Particles ◽  
Vt20 Alloy ◽  
Powder Particles ◽  
Vt20 Titanium Alloy

The study of unfavorable titanium alloy powders of VT20 grades was carried out and the methods of computer analysis were applied to determine the parameters of their optimal packaging. Metallographic studies were performed on a scanning electron microscope EVO-40XVP, and elemental analysis was performed using an energy dispersion spectrometer OXFORD INCA Energy 350. Determination of particle size distribution of powders was performed using image analysis software ImageJ. The surface morphology of non-spherical particles of VT20 alloy powder was studied for three different fractions: 100 ... 160 μm, 160 ... 200 μm and 200 ... 250 μm. It is shown that the powder particles are characterized by a nonspherical shape and a small difference in size. There is a tendency according to which when the particle size of the powder of the investigated alloy decreases, their shape approaches spherical. According to the results of particle size analysis, it was found that the usual sieve analysis does not allow to fully assess the distribution of powder by fractions. It was found that for the fraction 200 ... 250 μm the dominant particles are with an average diameter of 226 μm, for the fraction 160 ... 200 μm - 177 μm and for the fraction 100 ... 160 μm - 114 μm, respectively. Thus, for the fraction of titanium powder of the BT20 brand 200 ... 250 the polydispersity is 6.4%, for the fraction 160 ... 200 - 8.3%, and for the fraction 100 ... 160 - 9.1%. It is established that the fluidity of titanium alloy powders of the BT20 brand is: for the fraction 200 ... 250 μm - 62.35 s, for the fraction 160 ... 200 μm - 65.44 s, and for the fraction 100 ... 160 - 68, 73 s. That is, the highest value of fluidity is characterized by the powder with the largest particle size. Simulation of the pre-defined volume filling was performed using the "Spheres test" program. The average radii of particles of VT20 titanium alloy powder particles and the probability of the sizes of each of fractions of powder which is necessary at filling of the set volume was calculatedthe possibility of their precipitation have been established. Based on the obtained results, the packing density of VT20 titanium alloy powders was calculated depending on their fractional composition. It is confirmed that as the particle size of the powder decreases, their packing density increases. The surface morphology of non-spherical particles of VT20 alloy powder of different fractional composition and their particle size characteristics were studied. It is shown that with decreasing fractional composition of powder fractions, their homogeneity and bulk density increase. It was found that finer fractions are characterized by poorer fluidity. The simulation results determine the optimal fractional composition of the powder to fill the pre-specified volume. It is shown that as the size of the test particles decreases, their packing density increases. Keywords: additive production, titanium, microstructure, particle size distribution, bulk density, fluidity, packing density modelingmodelling.

Prediction of Packing Density of Milled Powder Based on Packing Simulation and Particle Shape Analysis

2007 ◽  
Vol 534-536 ◽  
pp. 1621-1624
Author(s):  
Yuto Amano ◽  
Takashi Itoh ◽  
Hoshiaki Terao ◽  
Naoyuki Kanetake
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Shape Analysis ◽  
Packing Density ◽  
Particle Shape ◽  
Milled Powder ◽  
Spherical Particles ◽  
Nonspherical Particles ◽  
Property Control

For precise property control of sintered products, it is important to know the powder characteristics, especially the packing density of the powder. In a previous work, we developed a packing simulation program that could make a packed bed of spherical particles having particle size distribution. In order to predict the packing density of the actual powder that consisted of nonspherical particles, we combined the packing simulation with a particle shape analysis. We investigated the influence of the particle size distribution of the powder on the packing density by executing the packing simulation based on particle size distributions of the actual milled chromium powders. In addition, the influence of the particle shape of the actual powder on the packing density was quantitatively analyzed. A prediction of the packing density of the milled powder was attempted with an analytical expression between the particle shape of the powder and the packing simulation. The predicted packing densities were in good agreement with the actual data.

Determination of Particle Size of a Dispersed Phase by Small-Angle X-ray Scattering

1989 ◽  
Vol 171 ◽  
Author(s):  
Frank C. Wilson
Keyword(s):  
Particle Size ◽  
High Resolution ◽  
Spherical Particles ◽  
Dispersed Phase ◽  
X Ray ◽  
X Ray Scattering ◽  
Resultant Data ◽  
Log Normal ◽  
Log Normal Distribution

ABSTRACTA method for determining particle diameters up to ca 500 rnm is described. X-ray data are obtained with an ultra-high resolution Bonse-Hart diffractometer and subsequently desmeared. The resultant data, viewed as the invariant argument h l(h), are interpreted as arising from a log-normal distribution of independent spherical particles. The distribution is characterized by its median value and breadth.

The Effect of Morphology and Particle-Size Distribution of VT20 Titanium Alloy Powders on the Mechanical Properties of Deposited Coatings

2019 ◽  
Vol 57 (11-12) ◽  
pp. 697-702 ◽  
Author(s):  
Z. A. Duriagina ◽  
I. A. Lemishka ◽  
A. M. Trostianchyn ◽  
V. V. Kulyk ◽  
S. G. Shvachko ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Titanium Alloy ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Vt20 Titanium ◽  
Vt20 Titanium Alloy

A Calculation Method for Packing Density of Powder in Paste with Continuous Grain Size Distribution

2011 ◽  
Vol 477 ◽  
pp. 125-131 ◽  
Author(s):  
Ye Guo ◽  
Xin Huang ◽  
Bao Lin Zhu
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Packing Density ◽  
Calculation Method ◽  
Particle System ◽  
Water Film ◽  
Cementitious Materials ◽  
Fly Ashes ◽  
Powder Particles ◽  
Continuous Particle

By regarding the powder particles warpped with water film as compounded particles, the packing density of powder particles in actual paste system is transformed into the packing density of compounded partcles in imaginary dry-particle system. Based on Stovall Model, a calculation method for packing density of powder with continuous particle size distribution in paste is developed, and the parameters in the method are dentified by experiment. This calculation method could be used to simulate the packing density of cementitious materials such as cement, fine slag, and fly ashes.

scholarly journals Analysis of mathematical models for description of the fractional composition of disperse elastic fillers

2019 ◽  
Vol 7 (5) ◽  
pp. 62-78 ◽  
Author(s):  
Yu. A. Naumova ◽  
I. V. Gordeeva
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Mathematical Models ◽  
Size Distribution ◽  
Fractional Composition ◽  
Cumulative Distribution ◽  
Normal Distribution Function ◽  
Rubber Powder ◽  
Powder Particles ◽  
Temperature Shear

The paper presents a comparative analysis of integral and differential mathematical models describing the particle size distribution of dispersed elastic fillers. Crushed vulcanizates obtained by high temperature shear grinding were studied as objects of research. Technogenic waste – waste passenger car tires and rubber elements of gas mask facepieces – were used as raw materials. Data on the distribution of the crushed vulcanizate particles were obtained by laser diffraction using the particle size analyzer Fritsch Analysette 22 Microtec plus (“Fritsch”, Germany). It was found that the distribution curves are unimodal asymmetric curves. Search and analysis of mathematical models were carried out using a specialized software product TableCurve 2D v5.01 (Jandel Scientific). Four- and five-parameter equations pertaining to the class of logistic models were tested to describe the integral cumulative distribution curves of the rubber powder particles. In order to justify the choice of a suitable mathematical model to describe the fractional composition of the crushed vulcanizes, the adequacy of the models was assessed, the structural characteristics of the variation series, the statistical moments of distribution and the indicators of its shape were determined. It was found that according to a number of criteria it is appropriate to use the logarithmically normal distribution function for the description and analysis of the rubber powders fractional composition. It is suggested that regardless of the nature of the feedstock, the described implementation of high temperature shear grinding provides products having an identical shape of rubber powder particles size distribution.

scholarly journals The influence of preparation factors on physical characteristics of chitosan nanoparticles

2020 ◽  
Vol 31 (3) ◽  
pp. 47-60
Author(s):  
Norra Shamiela Ruslan ◽  
◽  
Noratiqah Mohtar ◽  
Siti Sarah Fazalul Rahiman ◽  
Amirah Mohd Gazzali ◽  
...  
Keyword(s):  
Particle Size ◽  
Acetic Acid ◽  
Biomedical Applications ◽  
Chitosan Nanoparticles ◽  
Spherical Particles ◽  
Infrared Analysis ◽  
Naturally Occurring ◽  
Charge Shape ◽  
Positively Charged

Chitosan has been shown to have great potentials in various pharmaceuticals and biomedical applications, including drug delivery. Derived from chitin abundantly available in the shells of crustaceans such as crabs and shrimps, this naturally occurring polysaccharide is classified based on its molecular weight: low, medium or high. This study aimed to explore the production of chitosan nanoparticles (NP) and the influence of different factors on the physical properties of the NP produced. These factors were the concentrations of acetic acid, chitosan flakes and tripolyphosphate (TPP). The design of experiment (DoE) approach was used to determine the optimum conditions for the production of chitosan NP, with particle size (nm) and polydispersity index (PdI) being set as the responses. The chitosan flakes were solubilised in acetic acid at a specific concentration determined by the DoE before dropwise addition of TPP in an ice bath. The mixture was stirred at room temperature and subsequently centrifuged to remove the unformed materials, and then was spray-dried into powder. The size, surface charge, shape and morphology of the particles produced were characterised and infrared analysis was conducted. The results showed that the particles were spherical, slightly positively charged (ζ-potential: +2.89 at pH 7) and the infrared analysis displayed important peaks of the chitosan NP. The DoE results showed that not all combinations of parameters could produce NP; hence, determination of concentration for each parameter is essential. The equation produced by the DoE will be a useful guide to minimise error in this circumstance. In conclusion, the acetic acid and chitosan flakes concentrations were found to influence the particle size positively, whilst the increment in TPP concentration will adversely affect the particle size. Similar pattern of response was also observed for the PdI of the particles. The methods used in this study has successfully produced spherical particles, with evidence of interactions between TPP and chitosan in the NP as shown in the infrared spectrum.

Scattering of Light in Crystalline Polymers. I. Formation and Melting of the Crystalline Phase in Neoprene

1959 ◽  
Vol 32 (2) ◽  
pp. 463-470
Author(s):  
O. N. Trapeznikova ◽  
G. E. Smirnova
Keyword(s):  
Particle Size ◽  
Angular Distribution ◽  
Polarized Light ◽  
Melting Process ◽  
Spherical Particles ◽  
Scattering Method ◽  
Melting Range ◽  
Crystalline Polymers ◽  
Further Development

Abstract The process of formation and melting of neoprene crystallites was investigated by the polarized light scattering method. Conclusions about the nonreversibility of the crystallization and melting processes were drawn on the basis of angular distribution measurements of depolarized and polarized components of light scattered from polymer films. The appearance of a relatively small number of large crystallites is characteristic for the initiation of crystallization; further development of crystallization is accompanied by a decrease in the size of the crystallites. All crystallites disappear simultaneously during the melting process. The size of the crystallites determined by microphotography corresponds approximately to the particle size determined by the formula for isotropic, spherical particles. A method for the determination of the melting range of crystalline polymers is proposed.

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