THERMODYNAMIC AND KINETIC-STUDY OF DIFFUSION PATHS IN THE SYSTEM CU-AG-ZN

Diffusion paths were studied in the ternary Cu-Ag-Zn system between Cu -rich and Ag-rich solid solutions at 670 and 700 degrees C. The experi mental concentration profiles were converted to activity profiles usin g the assessed thermodynamic data. The analogy between solid/solid and solid/vapour/solid diffusion couples has been demonstrated. The pile- up of both concentration and activity for silver or copper as a matrix component has been shown to be caused by the dominating mobility of z inc. Using a combined thermodynamic and diffusion kinetic method the c oncentration dependence of the tracer diffusion coefficient of zinc at 670 degrees C has been calculated.