Electronic microscopy is based on the same principle as optical microscopy, with the only difference that the relevant rays are constituted by a group of electrons rather than visible light. The Scanning Electronic Microscope (SEM) enables a reflected image of the sample to be obtained (magnified up to 100,000 times or more) that highlights details (like the « depth effect ») that are otherwise impossible to observe. The SEM examination technique is used to study solid materials. The preparation of the sample consists of turning it into a conductor (if it is not already) by using a mix of carbon and layers of gold-palladium and includes variants depending on the materials and the purpose of the analysis.
Electronic micro-analysis by x-rays (SEM + Microprobe Energy-dispersive Spectroscopy (EDS))
This tool is extremely useful in studying surfaces; it has « x-ray microprobes » installed in the SEM. It consists of a system where the regular bombarding of the sample by electrons generates fluorescent x-rays. This device enables the chemical micro-analysis of the material, the reliability of which is exceptional.