Application of orthogonally arranged FIB–SEM for precise microstructure analysis of materials

► A new analytical tool based on a FIB–SEM double beam instrument is developed. ► The most characteristic point is that the FIB and SEM are arranged orthogonally. ► The plane sliced by the FIB is perpendicular to the incident electron beam direction. ► It makes possible to obtain high-quality 3D reconstruction from serial-sectioning. ► 3D analysis of precipitate distribution in a tempered martensitic steel is shown as an example of observation. In order to improve microstructure analysis with electron microscopes, we have developed an instrument that is based on a combination of a scanning electron microscope (SEM) and a focused ion beam (FIB). The most characteristic point is that the SEM and FIB are arranged orthogonally. The advantages of this orthogonal arrangement are that high-resolution and high-contrast SEM images can be obtained because of the uniform background intensity and the short working distance (≈2mm). Furthermore, since other analytical instruments (such as energy-dispersive spectroscopy (EDS), electron backscatter diffraction (EBSD), scanning transmission electron microscopy (STEM) equipment, etc.) can be located in their ideal positions, multiscale and versatile analyses can be performed with this single instrument. As an example, the observation of the distribution of precipitates in tempered martensitic steels is described. Because of the high contrast achieved by this instrument, different kinds of nanosized precipitates can be distinguished by the contrast in the 3D image reconstructed by the serial-sectioning method, even at low magnifications. Other features of the equipment are also described in this work.