Formation mechanism of amorphous silicon nanoparticles with additional counter-flow quenching gas by induction thermal plasma

Zhang, Xiaoyu; Liu, Zishen; Tanaka, Manabu; Watanabe, Takayuki

doi:10.1016/j.ces.2020.116217

Cited by 17 publications

(15 citation statements)

References 41 publications

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“…3b condensed and then surface atoms diffused to modify grain shapes and blur grain boundaries to form irregular shapes by the heat of plasma flame. Similar irregularly shaped nanoparticles were observed by condensation experiments of amorphous Si nanoparticles in high quenching gas (Zhang et al 2021). The high cooling rate may be a cause of the irregular shaped grains because the quenching rate of the grains at the upper wall of the chamber is higher than that at the lower wall.…”

Section: Condensation Processsupporting

confidence: 77%

Condensation of cometary silicate dust using an induction thermal plasma system I. Enstatite and CI chondritic composition

Kim,

Takigawa,

Tsuchiyama

et al. 2021

Preprint

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Glass with embedded metal and sulfides (GEMS) is a major component of chondritic porous interplanetary dust particles. Although GEMS is one of the most primitive components in the Solar System, its formation process and conditions have not been constrained. We performed condensation experiments of gases in the system of Mg-Si-O (MgSiO 3 composition) and of the S-free CI chondritic composition (Si-Mg-Fe-Na-Al-Ca-Ni-O system) in induction thermal plasma equipment. Amorphous Mg-silicate particles condensed in the experiments of the Mg-Si-O system, and their grain size distribution depended on the experimental conditions (mainly partial pressure of SiO). In the CI chondritic composition experiments, irregularly shaped amorphous silicate particles of less than a few hundred nanometers embedded with multiple Fe-Ni nanoparticles of ≤20 nm were successfully synthesized. These characteristics are very similar to those of GEMS, except for the presence of FeSi instead of sulfide grains. We propose that the condensation of amorphous silicate grains smaller than a few tens of nanometers and with metallic cores, followed by coagulation, could be the precursor material that forms GEMS prior to sulfidation.

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Section: Condensation Processsupporting

confidence: 77%

Condensation of cometary silicate dust using an induction thermal plasma system I. Enstatite and CI chondritic composition

Kim,

Takigawa,

Tsuchiyama

et al. 2021

Preprint

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“…In contrast, if the CH 4 injection position is characterized with a relatively low temperature, less amount of SiC are formed because the concentration of released C atoms is limited and most SiNPs already be solidi ed simultaneously. e high injection position in current research is nearest to the plasma torch and temperature is also higher than other two cases, which already be demonstrated with the numerical results in a paper before (Zhang et al, 2021a).…”

Section: Formation Mechanisms Of Sinps and Carbon Coatingsupporting

confidence: 76%

“…In plasma torch, the injected Si precursors are evaporated instantaneously because of the extremely high temperature. en silicon vapors are transported to reaction chamber with a steep temperature gradient, and the quenching rate for silicon vapors will be higher than 10 5 K/s (Zhang et al, 2021a). Subsequently, the saturation vapor pressure of silicon decreases rapidly.…”

Section: Formation Mechanisms Of Sinps and Carbon Coatingmentioning

confidence: 99%

Effect of Methane Injection Methods on the Preparation of Silicon Nanoparticles with Carbon Coating in Induction Thermal Plasma

Zhang

Yamano

Hayashida

et al. 2022

J. Chem. Eng. Japan

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Induction thermal plasma is applied to prepare carbon coated silicon nanoparticles as the anode materials of a battery and the e ect of methane injection methods is investigated. Silicon nanoparticles are fabricated as main products and show spherical morphologies with an average diameter of around 50 nm. The unfavorable formation of SiC, which is a byproduct and limits the practical capacity of batteries, can be identi ed when the methane injection position is near to plasma torch. An amorphous hydrogenated carbon coating is synthesized successfully instead of pure carbon materials. The CH 4 injection position can determine the decomposition temperature of methane as well as the concentration of released H atoms. Consequently, the properties of prepared carbon coatings, including the sp 2 ratio and H content, are tunable with injection positions through the etching e ect of hydrogen atoms. These results are signi cant for the synthesis of silicon nanoparticles with carbon coating and the design of lithium ion batteries with higher energy density.

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“…Even pure silicon nanoparticles are anticipated as promising materials for use in numerous applications such as lithography [ 2 ], electronic devices [ 3 ], electron transistors [ 4 , 5 ], floating gate memory devices [ 6 , 7 , 8 , 9 ], luminescent thermometers [ 10 ], and lithium ion battery electrodes [ 11 , 12 , 13 ]. Several Japanese groups have recently used thermal plasmas to achieve high-throughput production of silicon nanoparticles for lithium ion battery electrodes [ 14 , 15 , 16 , 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

“…Strong cross-correlations between the temperature at an upstream plasma fringe and nanoparticle concentration in a downstream region have been found for a transferred arc plasma system [ 26 , 27 ] and for a non-transferred arc plasma jet in two-dimensional [ 28 ] and three-dimensional fields [ 29 ] in recent numerical studies using a method suitable for simulating dynamic behaviors of thermal plasma–nonionized gas coexisting flows [ 30 ]. Actually, to control temperature and flow fields and to control nanoparticle growth processes in ICTP systems, several experimental studies adopted quenching strategies using a water-cooled coil [ 31 ], a water-cooled ball [ 15 , 32 ], direct plasma control by pulse modulation [ 33 ], counterflow injection [ 18 , 34 ], and radial gas injection [ 35 , 36 ]. Effects of those quenching methods were also investigated using two-dimensional simulations for practical conditions [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ].…”

Section: Introductionmentioning

confidence: 99%

Computational Study of Quenching Effects on Growth Processes and Size Distributions of Silicon Nanoparticles at a Thermal Plasma Tail

2021

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In this paper, quenching effects on silicon nanoparticle growth processes and size distributions at a typical range of cooling rates in a thermal plasma tail are investigated computationally. We used a nodal-type model that expresses a size distribution evolving temporally with simultaneous homogeneous nucleation, heterogeneous condensation, interparticle coagulation, and melting point depression. The numerically obtained size distributions exhibit similar size ranges and tendencies to those of experiment results obtained with and without quenching. In a highly supersaturated state, 40–50% of the vapor atoms are converted rapidly to nanoparticles. After most vapor atoms are consumed, the nanoparticles grow by coagulation, which occurs much more slowly than condensation. At higher cooling rates, one obtains greater total number density, smaller size, and smaller standard deviation. Quenching in thermal plasma fabrication is effectual, but it presents limitations for controlling nanoparticle characteristics.

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Formation mechanism of amorphous silicon nanoparticles with additional counter-flow quenching gas by induction thermal plasma

Cited by 17 publications

References 41 publications

Condensation of cometary silicate dust using an induction thermal plasma system I. Enstatite and CI chondritic composition

Condensation of cometary silicate dust using an induction thermal plasma system I. Enstatite and CI chondritic composition

Effect of Methane Injection Methods on the Preparation of Silicon Nanoparticles with Carbon Coating in Induction Thermal Plasma

Computational Study of Quenching Effects on Growth Processes and Size Distributions of Silicon Nanoparticles at a Thermal Plasma Tail

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