Effect of heating rate on kinetics of high-temperature reactions: Mo-Si system

By using the Computer Assisted Electrothermography (CAE) method and taking the molybdenum‐silicon system as an example, the influence of preheating rate on the kinetics of gasless reactions at high temperatures (above Si melting point, 1683 K) is studied. It is shown that an increase of heating rate...

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Bibliographic Details
Published in:AIChE journal 2005-01, Vol.51 (1), p.261-270
Main Authors: Kharatyan, Suren L., Chatilyan, Hakob A., Mukasyan, Alexander S., Simonetti, Dante A., Varma, Arvind
Format: Article
Language:English
Subjects:
Applied sciences
Chemical elements
Chemical engineering
Crystallization, leaching, miscellaneous separations
Effects
Exact sciences and technology
Heating
heating rate
High temperature
high-temperature reactions
Kinetics
molybdenum-silicon system
Reaction kinetics
reaction mechanism
Reactors
Silicon
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Summary:By using the Computer Assisted Electrothermography (CAE) method and taking the molybdenum‐silicon system as an example, the influence of preheating rate on the kinetics of gasless reactions at high temperatures (above Si melting point, 1683 K) is studied. It is shown that an increase of heating rate Vh in the range 10–105 K/s, leads to a substantial increase in the rate of chemical reaction. At high heating rates (>103 K/s), the first stage of interaction involves rapid reaction due to the direct dissolution of Mo in the Si melt. Furthermore, the formation of MoSi2 phase, owing both to crystallization from eutectic (MoSi2‐Si) melt and reaction‐diffusion mechanism, is primarily responsible for the observed intensive heat release under these conditions. At lower Vh, a thin layer of Mo5Si3 phase formed at earlier stages (solid‐solid interaction) significantly retards reaction at higher temperatures and changes the mechanism of interaction. Some methodological aspects of using the CAE technique for kinetic studies are also discussed. © 2004 American Institute of Chemical Engineers AIChE J, 51: 261–270, 2005
ISSN:0001-1541
1547-5905
DOI:10.1002/aic.10303