Chemical Analysis of Fracture Surfaces

Abstract

The applicability of various instrumental techniques for chemical analysis of fracture surfaces is reviewed. It is shown that methods which possess both a high spatial and a high in-depth resolution are usually required for analyzing structural heterogeneities on the fracture surface. When the features of interest have submicron dimensions, scanning Auger microanalysis (SAM) is most applicable, whereas features whose dimensions exceed 1 to 2 µm may be more easily characterized with scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDXA). Chemical analysis of fracture surfaces can also be used to investigate the atomistic mechanisms of crack propagation; this is of particular benefit when chemically-assisted crack growth is involved. In this case, a method with exceptional in-depth resolution is required to measure the composition of reaction products and modified surface layers in the fracture plane. In this regard, the unique capabilities of ion-scattering spectroscopy (ISS) and ion microscopy are also discussed.