Time exponent suppression of growth of the Zr-Sn diffusion layers between amorphous Zr₅₅Cu₃₀Al₁₀Ni₅ and Sn

The growth kinetics of the diffusion layer between molten Sn and Zr₅₅Cu₃₀Al₁₀Ni₅ bulk metallic glass (BMG) substrate were examined by isothermal aging at the temperature range between 513 and 633 K with 30 K temperature interval. The aged samples were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The growth of the diffusion layer is mainly controlled by a diffusion-controlled mechanism over the temperature range at stage I, and the value of the time exponent is approximately 1/2 by fitting the experiment data. As well as there is unusual stage II, whose time exponent of the growth is suppressed to 1/3. Based on phenomenological description, it could deduced that phase transition such like nucleation and coalescence occur in vicinity of the interface of diffusion layer at the late stage of clusters growth processes similar to Ostwald ripening.