Grain-boundary diffusion of germanium in copper and Cu-Ge and Cu-Fe alloys

The grain-boundary diffusion (GBD) of germanium in copper and its alloys Cu-2% Ge and Cu-0.5% Fe is investigated in the temperature range of 500?C590°C by means of electron-probe microanalysis. The GBD parameters (triple product P = s??D _GB and effective activation energy E) are found. The temperature dependence of the triple product for germanium GBD in pure copper can be described by equation P = 3 × 10¹⁵exp[?80 kJ mol^?1/(RT)] m³ s^?1. It is shown that the addition of Ge has almost no effect on the GBD parameters in copper, while doping with iron leads to a considerable reduction in the triple product.