Plasma synthesis of ceramic powders

Kong, Peter C.; Lau, Yuk-Chiu

doi:10.1351/pac199062091809

Cited by 59 publications

(18 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In the calculation, T 01 = 8,500 K and U 01 = 350 m/s have been chosen as the plasma jet-inlet temperature and velocity, as in [10]. Figures 2,3,4,5,6,7,8,9 present the modeling results for the case with the same plasma jet-inlet temperature and Figure 2 shows that due to the counter injection of the quenching gas, a distinct gasinterface layer with great temperature gradient (called as stagnation layer in Ref. [6]) is formed between the plasma torch exit and the counter-flow injector exit.…”

Section: Resultsmentioning

confidence: 99%

“…In early 1990s, a plasma reactor with counter-flow injection was developed in the High Temperature and Plasma Laboratory of the University of Minnesota and successfully employed for synthesizing various advanced ceramic powders including carbides, nitrides, oxides, solid solutions, etc. [3][4][5]. In such a reactor, particulate matter (e.g.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Modeling on the Momentum and Heat/Mass Transfer Characteristics of an Argon Plasma Jet Issuing into Air Surroundings and Interacting with a Counter-Injected Argon Jet

Wang

Chen

2011

Plasma Chem Plasma Process

View full text Add to dashboard Cite

Modeling study is performed to reveal the momentum and heat/mass transfer characteristics of a turbulent or laminar plasma reactor consisting of an argon plasma jet issuing into ambient air and interacting with a co-axially counter-injected argon jet. The combined-diffusion-coefficient method and the turbulence-enhanced combined-diffusioncoefficient method are employed to treat the diffusion of argon in the argon-air mixture for the laminar and the turbulent regimes, respectively. Modeling results presented include the streamline, isotherm and argon mass fraction distributions for the cases with different jetinlet parameters and different distances between the counter-injected jet exit and the plasma torch exit. It is shown that there exists a quench layer with steep temperature gradients inside the reactor; a great amount of ambient air is always entrained into the plasma reactor; and the flow direction of the entrained air, the location and shape of the quench layer are dependent on the momentum flux ratio of the plasma jet to the counterinjected cold gas. Two quite different flow patterns are obtained at higher and lower momentum flux ratios, and thus there exists a critical momentum flux ratio to separate the different flow patterns and to obtain the widest quench layer. There exists a high argon concentration or even 'air-free' channel along the reactor axis. No appreciable difference is found between the turbulent and laminar plasma reactors in their overall plasma parameter distributions and the quench layer locations, but the values of the critical momentum flux ratio are somewhat different.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling on the Momentum and Heat/Mass Transfer Characteristics of an Argon Plasma Jet Issuing into Air Surroundings and Interacting with a Counter-Injected Argon Jet

Wang

Chen

2011

Plasma Chem Plasma Process

View full text Add to dashboard Cite

show abstract

“…In other words, we anticipate that the temperature history of evaporated material |dT /dt| is |∂T /∂t + u · ∇T |. The rapid temperature history of K/s for evaporated material is known to be useful to create nanoparticle synthesis [18,19]. The other is the enhancement of the time-averaged temperature-gradient, which also causes cooling of evaporated material during transfer to the downstream chamber.…”

Section: Introductionmentioning

confidence: 99%

Influence of coil current modulation on TiO2 nanoparticle synthesis using pulse-modulated induction thermal plasmas

et al. 2011

View full text Add to dashboard Cite

This paper describes the relation between the size of synthesized nanoparticles and the temperature variation of the surrounding plasma in TiO 2 nanoparticle synthesis using pulse-modulated induction thermal plasmas (PMITP). The Ar-O 2 PMITP at 20 kW was used to obtain repetitional temperature fields at pressure of 200 Torr. The TiO 2 nanoparticles were synthesized by direct injection of Ti powder with mean diameter of 45 µm. Dependence of the nanoparticle size on modulation parameters such as the duty factor and the shimmer current level of the PMITP were investigated experimentally. Instantaneous temperature evolution was evaluated through spectroscopic observation. Experimental results show that the temperature decay rate in the PMITP reached 10 5 -10 6 K/s, and that the mean diameter of synthesized particles decreased with the temperature decay rate.

show abstract

“…Ultrafine oxide powders of specific ceramic materials are also used for catalytic applications. The conventional method of producing fine oxide powders involves controlled precipitation and pyrolysis of suitable salts [1]. The main limitation of high temperature decomposition route is the evolution of environmentally unacceptable and corrosive gas.…”

Section: Introductionmentioning

confidence: 99%