The self-diffusion and inter-diffusion in liquid Ce<sub>80</sub>Cu<sub>20</sub>
Abstract
The diffusion coefficient is not only a key parameter of liquid metal but also important to material design and forming. In this paper, the temperature dependent inter-diffusion coefficients in Ce<sub>80</sub>Cu<sub>20</sub> liquid metal are measured by the sliding cell method and self-diffusion coefficients are measured by neutron scattering technique. Both these two diffusion coefficients are well fitted by Arrhenius equation and the activation energy of inter-diffusion is close to that of the self-diffusion of Cu atom. It is found that the inter-diffusion coefficients are about 1.5 times larger than self-diffusion coefficients of copper atom. According to the data of Gibbs free energy, we calculate the thermal dynamic driving force (i.e. the thermal dynamic factor) for inter-diffusion of this alloy. The relation between self- diffusion and inter-diffusion in the present liquid alloy is discussed within the framework of Darken equation, which is usually used to describe the relation between self-diffusion and inter-diffusion in the solid crystalline alloy.
