SEMEBSD

SEM-EBSD stands for scanning electron microscope-electron backscatter diffraction. It is a microstructural characterization technique that combines the imaging capabilities of a SEM with the crystallographic information provided by EBSD to map the orientation and phase of crystalline materials.

In operation, the sample is placed in a SEM and tilted to about 70 degrees relative to the beam. When the focused electron beam interacts with the surface, backscattered electrons form Kikuchi diffraction patterns on an EBSD detector placed near the specimen. Software analyzes these patterns and indexes them to determine the crystal orientation at each scanned point. From these data, researchers produce orientation maps, phase maps, and grain boundary maps, often with grain size statistics and texture information. Misorientation criteria separate grain boundaries into low-angle and high-angle boundaries, commonly with thresholds around 2–5 degrees for low-angle boundaries and 15 degrees or more for high-angle boundaries; special boundaries may be identified based on specific misorientation relationships.

Outputs include color-coded orientation maps, which display local crystal directions; phase maps that distinguish different crystalline phases; and quantitative metrics such as grain size distributions, boundary character distributions, and texture strength. The technique is frequently used in metallurgy, ceramics, minerals, and other polycrystalline materials to study recrystallization, phase transformations, deformation mechanisms, and texture development.

Sample preparation requires a clean, smooth, and often conductive surface. Non-conductive samples typically need a coating or operation under low-vacuum conditions. Limitations include reliance on surface quality, resolution constrained by the interaction volume, and the need for crystalline order for pattern indexing.