The complete and accurate identification of all of the phases present in a sample is the ultimate goal of any materials investigator. The identification should include compositional as well as crystalline measurements for unique characterization. in an SEM, the composition of individual regions can be routinely determined via EDS or WDS analysis. The main limitation is the need to visually identify the individual regions from the images alone. A method to limit this restriction is to collect x-ray maps of the field-of-view. This technique has the benefit of providing the spatial distribution of the elemental species, but requires knowledge of all of the elements of interest before the start of the analysis and composition quantification cannot be performed with data only from the maps. Another disadvantage is the possibility that materials may have similar compositional analyses but may be different phases only manifested by crystallographic means.
A better method of complete phase identification involves the collection and analysis of spectral images and the subsequent crystallographic phase identification via EBSD. Spectral imaging consists of the collection of complete EDS spectra at each location within a field-of-view. From this 3-D data set, a series of elemental maps may be extracted for visualizing the spatial distribution of any elements of interest. This data set is especially useful because elements, and even characteristic x-ray lines, can be fully analyzed after the data collection with total flexibility.