Electron probe microanalysis: A review of recent developments and applications in materials science and engineering

Electron probe microanalysis (EPMA) is a microanalytical technique widely used for the characterization of materials. Since its development in the 1950s, different instrumental and analytical developments have been made with the aim of improving the capabilities of the technique. EPMA has utilized crystal diffractors with gas detectors (wavelength-dispersive spectrometers, WDS) and/or solid-state detectors (energy-dispersive spectrometers, EDS) to measure characteristic X-rays produced by an electron beam. In this review, we give an overview of the most significant methodological developments of EPMA that have occurred in the last three decades, including the incorporation of large area diffractors, field-emission guns, high-spectral resolution X-ray grating spectrometers, silicon drift detectors, as well as more powerful Monte Carlo simulations, which have opened a wide range of new possibilities for the characterization of materials using EPMA. The capabilities of the technique are illustrated by a selection of representative applications of EPMA to materials science and engineering, chosen to show the current merits and limitations of the technique. Given the lack of coverage in previous reviews of the excellent capabilities of EPMA for measurements of thin films and coatings, that topic is covered in detail. We finally provide ideas for new research opportunities using EPMA.