Interface width of immiscible layered elements

Abstract

Abstract Based on the thermodynamics of inhomogeneous systems, it is expected that the chemical transition at an interface between two immiscible components cannot be atomically sharp. However, measurements by direct local chemical analysis are rare, as utmost spatial resolution on an atomic scale is required. In this article, the temperature dependence of the chemical width of layer interfaces in binary Cu/Ag and ternary Cu/Ni81Fe19 specimens is studied experimentally. Atom probe techniques have been used to achieve sufficient spatial resolution. In both materials the interface width could be measured on a length scale of one to two nanometres. Its temperature dependence is found to be in agreement with the Cahn – Hilliard theory. From the measurements the gradient energy coefficient and the specific interfacial Gibbs energy are quantitatively determined.