The Study of Diffusion in Complex Metallic Liquids With High Melting Points -The Study of Self-Difusion and Mutual-Diffusion of Liquid Cu-Ag Alloys-

Abstract

The experiments of self and mutual diffusion coefficient measurements for liquid Cu-Ag alloys were performed un­der the microgravity of TR-IA-7 rocket with the use of diffusion couple method and shear cell technique. Measured temperatures were 1433, 1483 and 1533 K. The shear cell containing ten diffusion couples was developed. It worked successfully to create the liquid columns of all 30 diffusion couples and cutting of these liquid columns into divided pieces without any troubles. The obtained self diffusion coefficients for pure Cu and pure Ag were slightly spoiled by the effect of fluid motion. These data were compared with theoretically calculated values based on the hard sphere model, in which the hard sphere diameters are calculated from the thermodynamic variational theory. The present mutual diffusion data in liquid Cu-Ag alloys were also spoiled by the effect of fluid motion. Discussion is given to the cause of this fluid motion and it is concluded that careful attentions must be paid for the perfect performance of microgravity diffusion experiments particularly in the case of liquid mixtures.