Backscattering Kikuchi diffraction

Atlas of Backscattering Kikuchi Diffraction Patterns D J Dingley, K Z Baba-Kishi and V Randle ISBN 0 7503 0212 7... 

Other names instead of EBSD are Backscatter Kikuchi Diffraction (BKD), Electron Backscatter Pattern Technique (EBSP), Orientation Imaging Microscopy (OIM ), or Automated Crystal Orientation Mapping (ACOM). In combination with electrochemical studies only ex situ applications are possible. 

CONTEXT X-ray diffraction is the most common method for determining molecular structures within a crystal, but other methods are capable of faster, less detailed information about the crystal. For example, electron backscatter diffraction (also called backscatter Kikuchi diffraction), from a scanning electron microscope, measures the diffraction patterns of electrons that scatter off more than one plane in the crystal. From the patterns, the crystallographic point group, the orientation of the crystal, and the exposed Miller indices of the surface can be determined. Copper crystals, which have the advantage of simple structure, have been used to test the strengths and limitations of this method. 

Since its development in the 1970s and 1980s, the electron backscatter diffraction (EBSD) technique has become the most widely used method for micro-texture investigations in recent years [150,151]. The EBSD system is usually attached to a Scanning Electron Microscope. By arranging the specimen at an appropriate angle, an electron diffraction pattern can be generated and captured on film, a camera or a screen. The diffraction pattern is called a Kikuchi diffraction pattern, which consists of pairs of parallel lines, each of... 

Electron backscatter diffraction (EBSD) — The focused electron beam of Scanning Electron Microscopes (SEM) can be used to detect the crystallographic orientation of the top layers of a sample. The backscattered electrons (information depth 40-70 nm at 25 kV accelerating potential, lateral resolution around 200 nm) provide characteristic diffraction patterns (Kikuchi lines) on a phosphor screen. The patterns are recorded by a CCD-camera and interpreted by software. The position of the unit cell of the sample is determined by the corresponding Euler angles. In scanning mode, the software produces a surface orientation mapping that consists of... 

When the electrons impinge on the crystalline sample, they interact with individual lattice planes. When these interactions satisfy the Bragg condition, they exhibit backscattering diffraction and (due to the tilted sample) are directed toward a phosphor screen where the fluorescent pattern is detected by a CCD camera. The resulting pattern consists of a large number of intersecting bands, known as Kikuchi lines, which represent the unique crystallographic properties of the crystal... 

Also electron diffraction methods like electron backscatter diffraction (EBSD) can deliver phase information (see Fig. 4). EBSD, applied in scanning electron microscopes, assigns to each surface grain its phase affiliation and its orientation as a result of detected Kikuchi diagrams during specimen scanning (Schwartz et al. 2009). Figure 4 shows an EBSD analysis result for a two-phase titanium specimen. 

When the surfaces of the samples are crystalline, electron backscatter diffraction (EBSD) patterns, called Kikuchi lines, generated from reflected electrons, are observed. EBSD patterns provide knowledge concerning crystal stmctures and orientations. Thus, the combination of SEM and EBSD is one of the powerful tools, which can tell us the microstmctures of the sample surfaces and the orientations of the grains on the sample surfaces. 

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