A new experimental method to specify the diffusing component in a reacting particulate packing

Analysis of the solid-solid reaction rate has been made, based on the reaction mechanism controlled by the unidirectional diffusion, or by the counter diffusion of the components. To judge which is the diffusing component, the “marker” method has been used so far. However, due to the problems involved the results obtained are sometimes different by different workers even for the same system. The authors propose in this paper a new method to judge the diffusing component in accordance with the difference in the dependence of reaction rate upon the particle size ratio, which was developed in the course of our study on the model of solid-solid reactions. Examples are demonstrated by using the existing experimental data. On a effectue une analyse de la vitesse de reaction solide-solide, a partir du mecanisme de reaction controle par la diffusion unidirectionnelle ou par la contre-diffusion des composants. Jusqu'a ce jour, c'est la methode de «marquage» qui a ete utilisee pour determiner le composant diffusant. Cependant, en raison des problemes entraines, les resultats obtenus sont parfois differents selon les auteurs, meme pour des systemes identiques. On propose donc dans cet article une nouvelle methode de determination du composant diffusant; cette methode, mise au point au cours d'une etude sur la modelisation des reactions solide-solide, s'appuie sur l'influence de la taille des particules sur la vitesse de reaction. Des exemples sont presentes a partir de donnees experimentales existantes.