A Co-Condensation Model for In-Flight Synthesis of Metal-Carbide Nanoparticles in Thermal Plasma Jet
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JTTEE5 17:956–965 DOI: 10.1007/s11666-008-9240-y 1059-9630/$19.00 ASM International
A Co-Condensation Model for In-Flight Synthesis of Metal-Carbide Nanoparticles in Thermal Plasma Jet A. Vorobev, O. Zikanov, and P. Mohanty (Submitted June 11, 2008; in revised form July 28, 2008) We present a theoretical analysis of the formation, growth, and transport of two-component nanoparticles in thermal plasma jet. The approach of the aerosol science and the idea of multicomponent co-condensation are employed for the analysis. The processes of homogeneous nucleation, heterogeneous growth, and coagulations due to Brownian collisions are considered in combination with the convective and diffusive transport of particles and the reacting gases within an axisymmetric domain. As a particular example, the authors study multicomponent co-condensation of metal-carbide nanoparticles from various precursors in a DC plasma gun operating in an argon atmosphere.
Keywords
Brownian collisions, heterogeneous condensation, homogeneous nucleation, nanoparticles, numerical modeling, refractory coating, thermal plasma spraying
1. Introduction Metal carbides such as TaC, SiC, TiC are used in a wide range of industrial applications due to their excellent high temperature properties as well as chemical/wear resistance. The majority of these carbide powders are produced by carbothermic reduction. Alternatively, thermal plasma spraying is an excellent process for the preparation of metal carbide nanopowders from liquid/gaseous precursors due to its unique characteristics such as high temperature (>10,000 K), high chemical activity, and rapid quenching (~106-7 K/s). The use of thermal plasma spraying technique for production of nanopowders has been experimentally explored by several investigators (e.g., Ref 1-4). Several theoretical analyses also have focused on the synthesis of nanoparticles in different plasma reactors (Ref 1, 5-11). Most of the theoretical work devoted to the synthesis of nanoparticles is, however, This article is an invited paper selected from presentations at the 2008 International Thermal Spray Conference and has been expanded from the original presentation. It is simultaneously published in Thermal Spray Crossing Borders, Proceedings of the 2008 International Thermal Spray Conference, Maastricht, The Netherlands, June 2-4, 2008, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain Montavon, Ed., ASM International, Materials Park, OH, 2008. A. Vorobev, University of Southampton, Southampton, UK; and O. Zikanov and P. Mohanty, University of Michigan-Dearborn, Dearborn, MI. Contact e-mail: [email protected].
956—Volume 17(5-6) Mid-December 2008
focused on the nucleation and growth of particles consisting of one component. Recently, the authors developed an approach for modeling the in-flight synthesis of nanoparticles based on the concept of multicomponent co-condensation and descriptive tools of the aerosol science (Ref 12). Synthesis of TaC nanoparticles in atmospheric condit
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