Effect of Surface Movement on the Rate of Gas-Metal Reactions

Abstract

The present paper is concerned with the effect of surface movement on the rate of gas-metal reactions. Experimental studies were made by blowing argon-oxygen mixtures onto the silver melt heated electrically both by resistance and by high frequency induction. During the process of oxygen desorption from the melt of high oxygen concentration into the atmosphere of pure argon or the argon-oxygen mixture of very low oxygen potentials, the retardation of surface movement occurred and the surface became immobile. When the oxygen concentration of the melt became low, the surface movement recovered. On the other hand, in the case of oxygen absorption, the retardation of surface movement did not occur. The mass transfer coefficient for the immobile surface was smaller by a factor of about 7 than that for the mobile surface.

An analysis was made to explain the observed phenomena relating to the surface movement. By considering the shear stress due to the uneven distribution of the concentration of oxygen adsorbed on the surface leading to the uneven distribution of surface tension, the momentum boundary layer equation was solved. The analytical result gave a reasonable explanation for the experimental findings.