A method for measuring the interdiffusion coefficient in a liquid metal alloy. Application to the binary alloy Ag–Au
Christian Gonella, Annick Blanchet, Jacques Le Ny
An experimental method for measuring the interdiffusion coefficient, D, in a liquid alloy, based on measurement of the time dependence of a signal recorded by a mass spectrometer, is described. This signal is proportional to the surface composition which varies, during the diffusion, with respect to one of the two alloy elements. This experimental curve is fitted to a theoretical curve obtained by a numerical solution of the system of coupled equations. This method was applied to the alloy Ag – Au at 1430 K and the following equation is proposed for the variation of the interdiffusion coefficient with the composition: DAu-Ag/10-5 cm2 s-1 = 5.4 + 8.55 XAg – 8.17 X2Ag + 0.53X3Ag, where XAg is the atomic composition of silver in the binary alloy Ag – Au.