Adhesive force distributions for tungsten dust deposited on bulk tungsten and beryllium-coated tungsten surfaces

Tolias, Panagiotis; Riva, G.; Angeli, M. De; Ratynskaia, S.; Daminelli, Giambattista; Lungu, C.P.; Poroşnicu, C.

doi:10.1016/j.nme.2018.05.013

Cited by 18 publications

(14 citation statements)

References 43 publications

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“…In all cases, the low end of the distribution is cut off at 30 nN, as this represents the sensitivity of the force probe. Similar shapes for adhesion distributions have been reported previously for measurements in various contexts, including: centrifugal adhesion studies of particle adhesion in powders [40,41]; biological samples and cell adhesion [42,43] and many other studies using AFM adhesion measurements [44][45][46]. The origin of this distribution shape is not yet clear.…”

Section: Resultssupporting

confidence: 77%

Hard-material Adhesion: Which Scales of Roughness Matter?

et al. 2021

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Background Surface topography strongly modifies adhesion of hard-material contacts, yet roughness of real surfaces typically exists over many length scales, and it is not clear which of these scales has the strongest effect. Objective: This investigation aims to determine which scales of topography have the strongest effect on macroscopic adhesion. Methods Adhesion measurements were performed on technology-relevant diamond coatings of varying roughness using spherical ruby probes that are large enough (0.5-mm-diameter) to sample all length scales of topography. For each material, more than 2000 measurements of pull-off force were performed in order to investigate the magnitude and statistical distribution of adhesion. Using sphere-contact models, the roughness-dependent effective values of work of adhesion were measured, ranging from 0.08 to 7.15 mJ/m2 across the four surfaces. The data was more accurately fit using numerical analysis, where an interaction potential was integrated over the AFM-measured topography of all contacting surfaces. Results These calculations revealed that consideration of nanometer-scale plasticity in the materials was crucial for a good quantitative fit of the measurements, and the presence of such plasticity was confirmed with AFM measurements of the probe after testing. This analysis enabled the extraction of geometry-independent material parameters; the intrinsic work of adhesion between ruby and diamond was determined to be 46.3 mJ/m2. The range of adhesion was 5.6 nm, which is longer than is typically assumed for atomic interactions, but is in agreement with other recent investigations. Finally, the numerical analysis was repeated for the same surfaces but this time with different length-scales of roughness included or filtered out. Conclusions The results demonstrate a critical band of length-scales—between 43 nm and 1.8 µm in lateral size—that has the strongest effect on the total adhesive force for these hard, rough contacts.

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Section: Resultssupporting

confidence: 77%

Hard-material Adhesion: Which Scales of Roughness Matter?

et al. 2021

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“…In particular, value of adhesion energy for tungsten surfaces is still poorly documented and recent studies (Rondeau et al [2015], Peillon et al [2017], Tolias et al [2018]) are questioning data found in the literature for this material.…”

Section: Introductionmentioning

confidence: 96%

“…Other known methods like electrostatic detachment based on planar capacitor devices in which particles are exposed to increasing electric fields have been used extensively (Cho [1964], Cooper et al [1988], Takeuchi [2006], Szarek and Dunn [2007]). Very recently this method has been employed specifically for tungsten spherical particles deposited on tungsten substrates with the aim of determining detachment correlation between particle diameter and electric field detachment threshold (Riva et al [2017], Peillon et al [2017, Tolias et al [2018]). Such techniques make it possible to obtain the distribution of the adhesion forces for a large number of particles, thus with a good statistical representation.…”

Section: Introductionmentioning

confidence: 99%

Adhesion of tungsten particles on rough tungsten surfaces using Atomic Force Microscopy

Peillon

Autricque

Rédolfi

et al. 2019

Journal of Aerosol Science

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Adhesion forces between tungsten spherical microparticles and tungsten substrates with different roughnesses have been measured using the Atomic Force Microscopy (AFM) colloidal probe technique. Mean roughnesses of the tungsten substrates were measured by AFM and were ranked in three categories i.e. nanoscale, sub-microscale and microscale roughnesses. Experimental Hamaker constant of 37 ± 3.5 × 10 −20 J has been obtained using a spherical tungsten particle of 10.5 µm in radius and a tungsten substrate with nanoscale root-mean-square roughness of rms = 11.5 nm. It was shown that larger roughness of the order rms = 712 nm induces a two order of magnitude decrease on the adhesion of tungsten microparticles compared to a smooth tungsten surface with nanoscale roughness. Comparison with the van der Waals-based adhesion force model of Rabinovich which integrates the roughness of surfaces showed good agreement with experimental pull-off forces even when roughness of the substrate is close to the micrometer range. In such case, measurements have shown that dependency of adhesion force with particle size (in the micrometer range) has a secondary influence compared to the roughness of surfaces.

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“…Therefore, spherical tungsten powder with good flowability, high purity, and narrow particle size distribution is considered to be the most suitable feedstock material for AM of tungsten. In addition, spherical particles are assumed as the premise in some reported numerical models, such as theoretical models of contact and impact mechanics [ 16 ], analytical descriptions of adhesive interaction [ 17 ] and advanced models of particle resuspension [ 18 ]. Thus, their validation by experiments also requires the use of high-quality spheroidized powder.…”

Section: Introductionmentioning

confidence: 99%

Research on Spheroidization of Tungsten Powder from Three Different Raw Materials

et al. 2022

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In this work, three kinds of tungsten powders with different particle sizes were spheroidized by radio-frequency (RF) inductively coupled plasma spheroidization. The spheroidization behavior of these tungsten powders was investigated and compared. The spheroidization effects of irregular tungsten powder improves with the decrease in degree of agglomeration and increases with primary particle size. Spherical tungsten powder from irregular powder with a primary particle size of 19.9 μm and an agglomeration coefficient of 1.59 had the best spheroidization effect; its apparent density, hall flow time, and spheroidization ratio are 9.36 g/cm3, 6.28 s/50 g, and 98%, respectively. The results show that irregular feedstock tungsten powder with a smaller primary particle size and higher agglomeration degree has a poor spheroidization effect because it is easily affected by the gas flow and deviates from the high temperature zone. On the contrary, irregular feedstock tungsten powder with larger primary particle sizes and lower agglomeration degrees has better spheroidization effects.

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Adhesive force distributions for tungsten dust deposited on bulk tungsten and beryllium-coated tungsten surfaces

Cited by 18 publications

References 43 publications

Hard-material Adhesion: Which Scales of Roughness Matter?

Hard-material Adhesion: Which Scales of Roughness Matter?

Adhesion of tungsten particles on rough tungsten surfaces using Atomic Force Microscopy

Research on Spheroidization of Tungsten Powder from Three Different Raw Materials

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