Surface and grain-boundary segregation studied by quantitative AES and XPS

Abstract

Abstract Applied surface and interface analysis methods such as Auger electron spectroscopy and X-ray photoelectron spectroscopy are particularly well suited to studying intergranular segregation. In the case of internal interfaces such as grain boundaries, they must be transformed into two open surfaces by intergranular fracture. The main task is quantification of the measured spectra. Advantages and disadvantages of different approaches are discussed. It is shown that only for very low segregation levels do the simple and modified ratio methods give acceptable results. With increasing amount of enrichment, the more complicated methods with full description of the contribution of the first few monolayers to the total measured intensity have to be applied in order to obtain reliable concentration values that are useful for the determination of the concentration- and temperature-independent standard enthalpy and entropy of segregation.