SEM-EDX analysis (Scanning Electron Microscopy - X-ray Energy Dispersion Spectroscopy)

This is a material characterisation technique that combines two types of measurement: scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDX).

SEM produces three-dimensional images of the surface of samples with a resolution of up to a few nm and a very large depth of field. The composition of an image can be obtained from a secondary electron detector ("topographic" contrast, SE mode) and a backscattered electron detector ("chemical" contrast, BSE mode).

The difference lies in the origin of the contrast, which in BSE mode is linked to the nature of the elements present (e.g. the heavier the element, such as lead, the lighter the area).

EDX, on the other hand, identifies the chemical elements present in the sample from the X-rays emitted when it is bombarded by an electron beam. This technique provides information on the chemical composition of the sample on a microscopic scale, and can also be used to map the spatial distribution of chemical elements.

By combining SEM and EDX, it is possible to obtain information on the morphology, structure and chemical composition of a sample, making it a very useful technique for analysing materials in various fields such as materials science, geology, the study of metals, the study of paints, etc.