Induction Plasma Synthesis of Carbide Nano‐Powders

Leparoux, Marc; Schreuders, Cornelis; Shin, Jae Wook; Siegmann, S.

doi:10.1002/adem.200500046

Cited by 42 publications

(34 citation statements)

References 14 publications

(3 reference statements)

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“…1). According to modelling and enthalpy probe measurements [26,27], this position corresponds, for the process parameters used for SiC1 reference sample (see Table 1) to an axial plasma temperature of 3,000°C. In this paper, only the experiments performed with a constant quenching gas flow rate of 30 slpm are described.…”

Section: Experimental Methodsmentioning

confidence: 99%

Controlled Synthesis of β-SiC Nanopowders with Variable Stoichiometry Using Inductively Coupled Plasma

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Leparoux

Portier

et al. 2008

Plasma Chem Plasma Process

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In the growing field of nanomaterials, SiC nanoparticles arouse interest for numerous applications. The inductively coupled plasma (ICP) technique allows obtaining large amount of SiC nanopowders from cheap coarse SiC powders. In this paper, the effects on the SiC structure of the process pressure, the plasma gas composition, and the precursor nature are addressed. The powders were characterized by X-ray diffraction (XRD), Raman and fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and high resolution electron microscopy (HREM), chemical analyses, BET and photon correlation spectroscopy (PCS) measurements. Whatever the precursor (a-or b-SiC), the nanoparticles were crystallised in the cubic b-SiC phase, with average sizes in the 20-40 nm range. Few residual grains of precursor were observed, and the decarburization due to the reductive Ar-H 2 plasma lead to the appearance of Si nanograins. The stoichiometry of the final product was found to be controllable by the process pressure and the addition of methane.

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Section: Experimental Methodsmentioning

confidence: 99%

Controlled Synthesis of β-SiC Nanopowders with Variable Stoichiometry Using Inductively Coupled Plasma

Leconte

Leparoux

Portier

et al. 2008

Plasma Chem Plasma Process

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“…[9] Its dimensions and its geometry have been introduced in the CFD modelling code. Plasma gases typically used for processing are argon and hydrogen.…”

Section: Experimental Set-up and Plasma Characterizationmentioning

confidence: 99%

Improved Plasma Synthesis of Si‐nanopowders by Quenching

2008

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Silicon nanopowders are investigated intensively for application in microelectronics and energy among them. [1][2][3] However, for the moment the control of the product high quality and the processing costs are limiting their breakthrough. RF-thermal plasmas could respond to both criteria as it is a continuous process achieving high production volume while ensuring a good synthesis control from the gaseous phase. The absence of electrodes for igniting the plasma and the controlled process atmosphere of RF-plasmas are beneficial for producing high purity materials. Typically a supersaturated gaseous phase containing the precursor is condensed rapidly after nucleation took place. The nanoparticles grow then subsequently by coagulation and coalescence. [4] This rapid condensation is achieved either by natural thermal gradients in the plasma or by quenching using a cold source (gas or cold surface) or by using an expansion. [5][6][7][8] This paper addresses the development of a specific quenching nozzle design combining rapid cooling with an expansion for controlling the size of silicon nanopowders processed by an inductively coupled plasma (ICP). The design of the quenching device has been supported by computational fluid dynamic (CFD) calculations aiming at modelling the plasma properties like among them the temperature and the velocity of the powderfree plasma. The modelling has been validated by in-situ plasma characterization using an enthalpy-probe coupled to a mass spectrometer. The produced nanopowders were collected either on a filter membrane, or directly in the gas phase using an on-line and in-situ sampling system made of a TEM-grid fixed on a moveable support and then ex-situ characterized by XRD, Raman, microscopy and surface specific area measurement using the BET technique. Experimental Set-up and Plasma CharacterizationThe ICP apparatus devoted to the synthesis of nanoparticles has been already described in details elsewhere. [9] Its dimensions and its geometry have been introduced in the CFD modelling code. Plasma gases typically used for processing are argon and hydrogen. This reducing atmosphere is generally used to ensure oxide-free particles. The plasma torch (PL-35, Tekna) has been also modelled with the different gas inlets; carrier gas (Ar), central gas (Ar) and the sheath gas that is a mixture of Ar and H 2 . The gas composition is referred in the following as carrier gas-central gas-sheath gas (Ar/H 2 ) in slpm. An enthalpy-probe (ENT-476, Tekna) has been used to measure in-situ the enthalpy and the velocity of the plasma in powder-free conditions at different radial positions and heights in the reactor (z=0 corresponds to the plasma torch exhaust). The plasma properties have been calculated outside the electromagnetic field, meaning below the torch exhaust where the quenching should be performed. Therefore, in a first approximation, the plasma process has been considered as a steady state process with the plasma being modelled as a heat source with a homogeneous power distribution located ...

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“…The process parameters have already been described and simulated by a group in Empa Thun [5,6]. Among these technologies, we report here the synthesis of SiC nanopowders by inductively coupled plasma (ICP) and laser pyrolysis.…”

Section: Introductionmentioning

confidence: 99%

Structural Study of SiC Nanoparticles Grown by Inductively Coupled Plasma and Laser Pyrolysis for Nanostructured Ceramics Elaboration

et al. 2006

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Refractory carbide nanostructured ceramics as SiC constitute interesting materials for high temperature applications and particularly for fourth generation nuclear plants. To elaborate such nanomaterials, weighable amounts of SiC nanopowders have to be synthesized first with an accurate control of the grain size and stoichiometry. The inductively coupled plasma and the laser pyrolysis techniques, respectively developed at EMPA Thun and CEA Saclay, allow meeting these requirements. Both techniques are able to produce dozens of grams per hour of silicon carbide nanopowders. The particle size can be adjusted down to around 20 nm for the plasma synthesis and even down to 5-10 nm for the laser pyrolysis. The stoichiometry Si/C can be tuned by the addition of methane into the plasma and acetylene for the laser process.

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Induction Plasma Synthesis of Carbide Nano‐Powders

Cited by 42 publications

References 14 publications

Controlled Synthesis of β-SiC Nanopowders with Variable Stoichiometry Using Inductively Coupled Plasma

Controlled Synthesis of β-SiC Nanopowders with Variable Stoichiometry Using Inductively Coupled Plasma

Improved Plasma Synthesis of Si‐nanopowders by Quenching

Structural Study of SiC Nanoparticles Grown by Inductively Coupled Plasma and Laser Pyrolysis for Nanostructured Ceramics Elaboration

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