Fluidization of Nanoparticle Agglomerates at Elevated Temperatures

Esmailpour, Ali Asghar; Mostoufi, Navid; Zarghami, Reza

doi:10.1021/acs.iecr.7b02921

Cited by 8 publications

(4 citation statements)

References 41 publications

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“…While SAC0307 and Cu particles are nanoparticles, when the temperature increases, SAC0307 nanoparticles with a lower melting point gradually melt, and a large number of positive or negative charges are accumulated on the surface of Cu nanoparticles with a higher melting point, and the particle shape becomes irregular, which makes the surface charges of the Cu particles gather and become unstable. Moreover, the nanoparticles have a larger specific surface area and higher surface energy, so it is easy to form agglomerated Cu particles with lower surface energy (Esmailpour et al , 2017; Yang et al , 2022). Figure 8(c) is the ultrasonic loading stage in the soldering process.…”

Section: Resultsmentioning

confidence: 99%

Properties of Cu/Zn+15%SAC0307+15%Cu/Al joints by different ultrasonic-assisted degrees

Huang

Gan

Liu

et al. 2023

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Purpose This paper aims to investigate the effects of different ultrasonic-assisted loading degrees on the microstructure, mechanical properties and the fracture morphology of Cu/Zn+15%SAC0307+15%Cu/Al solder joints. Design/methodology/approach A new method in which 45 μm Zn particles were mixed with 15% 500 nm Cu particles and 15% 500 nm SAC0307 particles as solders (SACZ) and five different ultrasonic loading degrees were applied for realizing the soldering between Cu and Al at 240 °C and 8 MPa. Then, SEM was used to observe and analyze the soldering seam, interface microstructure and fracture morphology; the structural composition was determined by EDS; the phase of the soldering seam was characterized by XRD; and a PTR-1102 bonding tester was adopted to test the average shear strength. Findings The results manifest that Al–Zn solid solution is formed on the Al side of the Cu/SACZ/Al joints, while the interface IMC (Cu5Zn8) is formed on the Cu side of the Cu/SACZ/Al joints. When single ultrasonic was used in soldering, the interface IMC (Cu5Zn8) gradually thickens with the increase of ultrasonic degree. It is observed that the proportion of Zn or ZnO areas in solders decreases, and the proportion of Cu–Zn compound areas increases with the variation of ultrasonic degree. The maximum shear strength of joint reaches 46.01 MPa when the dual ultrasonic degree is 60°. The fracture position of the joint gradually shifts from the Al side interface to the solders and then to the Cu side interface. Originality/value The mechanism of ultrasonic action on micro-nanoparticles is further studied. By using different ultrasonic loading degrees to realize Cu/Al soldering, it is believed that the understandings gained in this study may offer some new insights for the development of low-temperature soldering methodology for heterogeneous materials.

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Section: Resultsmentioning

confidence: 99%

Properties of Cu/Zn+15%SAC0307+15%Cu/Al joints by different ultrasonic-assisted degrees

Huang

Gan

Liu

et al. 2023

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“…The visual observation seems more reliable and better than ex situ analysis of sampled FNPAs; however, there exists an obvious limitation for this technique in that it is only capable of measurements of the size and terminal velocity for the FNPAs. For some ex situ analyses, such as the observation of the morphology of FNPAs by SEM, the midupper FNPAs are always sampled from the bed with an adhesive tape or by aspiration in recent years. ,,,, The biggest challenge is to sample the FNPAs out of the bed without disrupting their sizes or structures. In the experiments, FNPAs are sampled through the sampling port by aspiration at the bottom of the bed.…”

Section: Methodsmentioning

confidence: 99%

“…For some ex situ analyses, such as the observation of the morphology of FNPAs by SEM, the midupper FNPAs are always sampled from the bed with an adhesive tape or by aspiration in recent years. 6,12,13,30,31 The biggest challenge is to sample the FNPAs out of the bed without disrupting their sizes or structures. In the experiments, FNPAs are sampled through the sampling port by aspiration at the bottom of the bed.…”

Section: Methodsmentioning

confidence: 99%

Structure and Drag Characteristics of Fluidized Nanoparticle Agglomerates at the Bottom of the Bed

Liu

Yang

2019

Ind. Eng. Chem. Res.

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The shape, size, density, and porosity of fluidized nanoparticle agglomerates (FNPAs) at the bottom of a fluidized bed were studied, the internal microscopic structures were revealed by the transmission electron microscopy observation of slices of the solidified FNPAs, and the drag coefficients were measured by the settling experiments. The results show that the distributions of diameter, density, and porosity all follow the Gaussian distribution. They have a similar hierarchical structure to FNPAs in the middle and upper parts of the bed. Primary nanoparticles connect to form aggregates of a few hundred nanometers, which then form simple agglomerates of several micrometers. The total porosities of FNPAs are in the range of 0.92−0.99, and the porosities between simple agglomerates, ε s,out , are in the range of 0.44−0.93. The values of the drag ratio, Ω, are larger than 1, around 1, and lower than 1 when values of ε s,out are in the ranges of ≤0.58, 0.58−0.77, and >0.77, respectively.

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“…[73] Moreover, the airflow velocity as a function of voidage around the fluidized agglomerates follows the Richardson-Zaki equation. [31,55,74] Navid et al [75] investigated the fluidization behavior of hydrophobic nanoparticles at low temperatures and discovered their remarkable bed expansion, resulting in stable and uniform fluidization without bubble formation. Conversely, hydrophilic nanoparticles exhibit APF behavior at high temperatures due to temperature-induced changes in hydrogen bonding and vdW force between particles.…”

Section: Agglomerate Particulate Fluidizationmentioning

confidence: 99%

Fluidization and Application of Carbon Nano Agglomerations

Chen,

Jiang,

Zhu

et al. 2023

Advanced Science

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Carbon nanomaterials are unique with excellent functionality and diverse structures. However, agglomerated structures are commonly formed because of small‐size effects and surface effects. Their hierarchical assembly into micro particles enables carbon nanomaterials to break the boundaries of classical Geldart particle classification before stable fluidization under gas‐solid interactions. Currently, there are few systematic reports regarding the structural evolution and fluidization mechanism of carbon nano agglomerations. Based on existing research on carbon nanomaterials, this article reviews the fluidized structure control and fluidization principles of prototypical carbon nanotubes (CNTs) as well as their nanocomposites. The controlled agglomerate fluidization technology leads to the successful mass production of agglomerated and aligned CNTs. In addition, the self‐similar agglomeration of individual ultralong CNTs and nanocomposites with silicon as model systems further exemplify the important role of surface structure and particle‐fluid interactions. These emerging nano agglomerations have endowed classical fluidization technology with more innovations in advanced applications like energy storage, biomedical, and electronics. This review aims to provide insights into the connections between fluidization and carbon nanomaterials by highlighting their hierarchical structural evolution and the principle of agglomerated fluidization, expecting to showcase the vitality and connotation of fluidization science and technology in the new era.

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Fluidization of Nanoparticle Agglomerates at Elevated Temperatures

Cited by 8 publications

References 41 publications

Properties of Cu/Zn+15%SAC0307+15%Cu/Al joints by different ultrasonic-assisted degrees

Properties of Cu/Zn+15%SAC0307+15%Cu/Al joints by different ultrasonic-assisted degrees

Structure and Drag Characteristics of Fluidized Nanoparticle Agglomerates at the Bottom of the Bed

Fluidization and Application of Carbon Nano Agglomerations

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