Prediction of Surface Segregation in Binary Alloys Using Bulk Alloy Variables

A simple graphical approach is proposed which correctly predicts the occurrence or absence of surface segregation for virtually all binary alloys that have been studied experimentally. The rule is based on elemental variables related to the work functions and electron densities of the elements. These variables have been proposed by Miedema and used by him to predict binary-alloy heats of solution and elemental surface energies. The graphical condition for segregation is derived analytically and is valid for both substitutional and interstitial alloys.