Influence of particle shape and size on the wetting behavior of soft magnetic micropowders

Kirchberg, Stefan; Abdin, Yasmine; Ziegmann, Gerhard

doi:10.1016/j.powtec.2010.11.012

Cited by 52 publications

(29 citation statements)

References 16 publications

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“…The apparent contact angle does decrease for smaller particles; see e. g. . Thus, below a critical diameter, wetting is prohibited, or at least slowed down.…”

Section: Resultsmentioning

confidence: 99%

Solid‐Liquid Adhesion Energies of Composite Propellant Components Determined by Solution Calorimetry

Nardai

Bohn

2017

Propellants Explo Pyrotec

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The energetic or adhesive interaction between binder matrix and solid fillers as well as plasticizers and fillers is a property determining mechanical properties as strain capacity and stress at maximum or stress at break. To know such interaction energies is therefore of interest. An isoperibolic solution calorimeter is used to measure such interaction energies or heats of immersion of the solid propellant components ammonium perchlorate (AP) and aluminium (AL) with the liquid plasticizers bis‐(2‐ethylhexyl) adipate (DEHA) and azido‐terminated oligomeric glycidylazide (GAP−A). The determined heats indicate wettability and interaction energy in units of energy per surface area of the solid component. For AP, three different grain sizes with mean diameter about 200, 90, 42 μm were used. Results indicate dependence of AP wetting on mean particle diameter: Successful wetting occurs for AP at diameters from above 90 μm. The polar interactions between the ionic AP and GAP−A greatly enhance wetting as compared to DEHA.

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“…The apparent contact angle does decrease for smaller particles; see e. g. . Thus, below a critical diameter, wetting is prohibited, or at least slowed down.…”

Section: Resultsmentioning

confidence: 99%

Solid‐Liquid Adhesion Energies of Composite Propellant Components Determined by Solution Calorimetry

Nardai

Bohn

2017

Propellants Explo Pyrotec

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“…In this method, packing of particles is also important since it may affect the penetration rate of the wetting liquid and thus the measured value of the contact angle Kirchberg et al, 2011).…”

Section: Resultsmentioning

confidence: 99%

“…A contact angle of 72-75° (Kirchberg et al, 2011) was reported for unsieved magnetite powder with a particle size of 6146 lm and irregular particle shape. For the magnetite with a size of 86% À74 lm, the contact angle was determined to be 46° (Qiu et al, 2004).…”

Section: Resultsmentioning

confidence: 99%

Interfacial properties of natural magnetite particles compared with their synthetic analogue

Potapova

Yang

Westerstrand

et al. 2012

Minerals Engineering

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a b s t r a c tUnderstanding of the interactions between iron oxides and flotation reagents is important both for flotation and agglomeration of iron ore. Model systems comprising synthetic iron oxides and pure chemical reagents are commonly applied in experimental work in order to obtain high quality data and to ease the interpretation of the empirical data. Whether the results obtained using model systems are valid for iron ore minerals and commercial reagents is a question seldom addressed in the literature. It is shown in this work that previously reported results obtained from a model system, concerning adsorption of a carboxylate surfactant and sodium metasilicate onto synthetic magnetite nanoparticles, as obtained by in situ ATR-FTIR spectroscopy and contact angle measurements, are applicable to adsorption of flotation reagents on magnetite concentrate. Additionally, the problem of restoring magnetite wetting after flotation is addressed since good wetting of a magnetite concentrate is required to produce iron ore pellets by wet agglomeration. The results from the present work indicate that the wettability of both synthetic magnetite coated with surfactant and magnetite concentrate after flotation can be improved by adsorbing a hydrophilizing agent such as silicate or polyacrylate.

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“…This is a quantitative confirmation of the varying wetting behaviors of the powders. Favorable wetting is indicated at contact angles below 90 ° , while powders with more than 120 ° contact angles will be nonwetting …”

Section: Methodsmentioning

confidence: 99%

“…Favorable wetting is indicated at contact angles below 90°, while powders with more than 120°c ontact angles will be nonwetting. 19,20 Laser sizing was done to obtain the PSDs, using the Malvern laser The atomized sample shows spheroidal and prolate particles ( Figure 1A), while the milled samples show angular granular particles ( Figure 1B-D). This shape distinction is expected as the production routes are clearly different and has been well reported.…”

Section: Introductionmentioning

confidence: 99%

Understanding hydrophobicity variations in dense medium ferrosilicon from different production routes

Otunniyi

Oluokun

2019

Surface & Interface Analysis

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Dense medium ferrosilicon (FeSi) powders produced via submerged arc furnace smelting, granulation, and milling route show varying hydrophobicity, sometimes totally nonwetting, amounting to production losses. This does not occur in powders produced via induction furnace smelting and atomization. Although wetting is fundamentally a surface phenomenon, bulk property can dictate surface behavior. Hence, for detailed insight into the cause of the variation, particles of powders from different production routes were studied from surface to the core. Particle shapes differ clearly for the two production routes, but this was found inconsequential to the wetting behavior. Rather, size distribution, proportion of ultra‐fine particles in the powder, was seen to have effect, being more in the nonwetting sample. From the optical microscopy: in the granular particles (that is, before milling), it is visible that different phases formed from the Fe‐Si‐C system, and this will impact milling differently; particles from nonwetting milled powders show a notable surface layer, and in contrast, the atomized particles show more homogeneous equiaxed grains. From X‐ray photoelectron spectroscopy, argon ions sputtering, and depth composition profiling, graphitic carbon (C1s at 284.5 eV binding energy) was found on the surface for all samples at levels above bulk alloy composition but highest (65%) for the totally nonwetting sample. From these pointers, graphite coating on particles is responsible for varying hydrophobicity. Carbon affects solid FeSi microstructure, milling, and powder properties. Controlling carbon content from the smelting stands out for avoiding milled FeSi hydrophobicity. This is however not a straight forward minimization problem.

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Influence of particle shape and size on the wetting behavior of soft magnetic micropowders

Cited by 52 publications

References 16 publications

Solid‐Liquid Adhesion Energies of Composite Propellant Components Determined by Solution Calorimetry

Solid‐Liquid Adhesion Energies of Composite Propellant Components Determined by Solution Calorimetry

Interfacial properties of natural magnetite particles compared with their synthetic analogue

Understanding hydrophobicity variations in dense medium ferrosilicon from different production routes

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