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外文期刊>International Journal of Heat and Mass Transfer
>ROLE OF INTER-AND INTRAPARTICLE DIFFUSION IN NONUNIFORM PARTICLE SIZE GASLESS COMPACTED POWDER COMBUSTION SYNTHESIS-II: RESULTS AND COMPARISON WITH EXPERIMENT
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ROLE OF INTER-AND INTRAPARTICLE DIFFUSION IN NONUNIFORM PARTICLE SIZE GASLESS COMPACTED POWDER COMBUSTION SYNTHESIS-II: RESULTS AND COMPARISON WITH EXPERIMENT
Following Part I, the predicted results of a combined three-scale, specimen-level/particle-level treatment of gasless, combustion synthesis of intermetallics, for a system with specimen-level composition corresponding to Tial_3, is presented. It is shown that the intraparticle diffusion, modeled by a high reaction rate (i.e.,primary-diffusion) regime followed by a lower reaction rate (i.e., secondary-diffusion) regime, determines the front structure adn the propagation speed. The nonuniform particle-size distribution limits the availability of the reactants at a particle level, thus determining the extent of conversion to the final product and the maximum temperature. Experiments are performed for the aluminium-titanium system for two different titanium( higher melting temperature reactant) powder sizes. The model predicts a lower conversion than that observed in the experiments, indication the importance of interparticle diffusion. There is good agreement between the predicted and measured variations of propagation speed and maxiumum temperature with respect to the average particle size.
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