Phase Identification of Individual Particles by Electron Backscatter Diffraction (EBSD)

1999 ◽  
Vol 5 (S2) ◽  
pp. 226-227 ◽  
Author(s):  
J. Small ◽  
J. Michael
Keyword(s):  
Electron Backscatter Diffraction ◽  
Ccd Camera ◽  
Practical Method ◽  
Rapid Identification ◽  
Photographic Film ◽  
Reference Image ◽  
Phase Identification ◽  
Electron Backscatter ◽  
Backscattered Electron ◽  
Backscatter Diffraction

Backscattered electron Kikuchi patterns (BEKP) were first observed by Alam et al. in 1954. J.A. Venables and C.J. Harland made the initial observation of BEKP and in the scanning electron microscope in 1973. In 1996, Goehner and Michael developed an electron backscatter diffraction (EBSD) system that uses a 1024 × 1024 pixel CCD camera coupled to a thin scintillator rather than photographic film. In their system, the quality of the raw patterns is improved by the use of “flat fielding” which normalizes the raw image to a “flat field” reference image that contains the image artifacts, including background, but not the crystallographic information. Automated pattern analysis is carried out using a Hough transform to locate bands and band edges in the pattern. The resulting crystallographic information is coupled with the elemental information from energy or wavelength dispersive x-ray spectrometry and the phase is identified is made through a link to a database such as the Powder Diffraction Files published by ICDD. An indexed pattern of the suspected phase is then synthesized for comparison to the unknown. This system is marketed commercially by Noran Instruments and offers the first practical method for rapid identification of unknown crystallographic phases in the SEM.

All You Need to Know About Electron Backscatter Diffraction: Orientation is Only the Tip of the Iceberg

1997 ◽  
Vol 3 (S2) ◽  
pp. 387-388 ◽  
Author(s):  
J. R. Michael
Keyword(s):  
Electron Backscatter Diffraction ◽  
Photographic Film ◽  
Phase Identification ◽  
Electron Backscattered Diffraction ◽  
Bulk Specimen ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Over 40 Years ◽  
Orientation Determination ◽  
Scanning Electron

This tutorial will describe the technique of electron backscattered diffraction (EBSD) in the scanning electron microscope (SEM). To properly exploit EBSD in the SEM it is important to understand how these patterns are formed. This discussion will be followed by a description of the hardware required for the collection of electron backscatter patterns (EBSP). We will then discuss the methods used to extract the appropriate crystallographic information from the patterns for orientation determination and phase identification and how these operations can be automated. Following this, a number of applications of the technique for both orientation studies and phase identification will be discussed.EBSD in the SEM is a phenomenon that has been known for many years. EBSD in the SEM is a technique that permits the crystallography of sub-micron sized regions to be studied from a bulk specimen. These patterns were first observed over 40 years ago, before the development of the SEM and were recorded using a special chamber and photographic film.

Electron Backscatter Diffraction in Conservation Science: Phase Identification of Pigments in Paint Layers

2013 ◽  
Vol 19 (4) ◽  
pp. 921-928 ◽  
Author(s):  
A. Gambirasi ◽  
L. Peruzzo ◽  
S. Bianchin ◽  
M. Favaro
Keyword(s):  
Cross Sections ◽  
Electron Backscatter Diffraction ◽  
Small Samples ◽  
Phase Identification ◽  
Conservation Science ◽  
Atomic Number Density ◽  
Electron Backscatter ◽  
Mohs Hardness ◽  
Backscatter Diffraction ◽  
First Time

AbstractElectron backscatter diffraction (EBSD) was used in Conservation Science for characterization of ancient materials collected from works of art. The results demonstrate the feasibility of EBSD analysis on heterogeneous matrices as very small samples of paint layers collected from paintings. Two reference pigments were selected from those used by artists to investigate the relationship existing between EBSD pattern quality and properties of the investigated material (i.e., average atomic number, density, and Mohs hardness). The technique was also tested to investigate the pigment phases on two real samples collected from Romanino's Santa Giustina altarpiece, an oil on wood painting dated 1514 (Civic Museum, Padova, Italy). Results show for the first time the acquisition of EBSD patterns from painting samples mounted in resin, i.e., painting cross sections, opening a new powerful tool to elucidate the pigment phases avoiding large sampling on works of arts and to further study the complex mechanisms of pigment deterioration.

scholarly journals Automated Reconstruction of Spherical Kikuchi Maps

2019 ◽  
Vol 25 (4) ◽  
pp. 912-923 ◽  
Author(s):  
Chaoyi Zhu ◽  
Kevin Kaufmann ◽  
Kenneth Vecchio
Keyword(s):  
Electron Backscatter Diffraction ◽  
Phase Identification ◽  
Threshold Values ◽  
Kikuchi Pattern ◽  
Electron Backscatter ◽  
Multiple Scan ◽  
Multiple Threshold ◽  
Diffraction Patterns ◽  
Backscatter Diffraction ◽  
Pattern Center

AbstractAn automated approach to fully reconstruct spherical Kikuchi maps from experimentally collected electron backscatter diffraction patterns and overlay each pattern onto its corresponding position on a simulated Kikuchi sphere is presented in this study. This work demonstrates the feasibility of warping any Kikuchi pattern onto its corresponding location of a simulated Kikuchi sphere and reconstructing a spherical Kikuchi map of a known phase based on any set of experimental patterns. This method consists of the following steps after pattern collection: (1) pattern selection based on multiple threshold values; (2) extraction of multiple scan parameters and phase information; (3) generation of a kinematically simulated Kikuchi sphere as the “skeleton” of the spherical Kikuchi map; and (4) overlaying the inverse gnomonic projection of multiple selected patterns after appropriate pattern center calibration and refinement. The proposed method is the first automated approach to reconstructing spherical Kikuchi maps from experimental Kikuchi patterns. It potentially enables more accurate orientation calculation, new pattern center refinement methods, improved dictionary-based pattern matching, and phase identification in the future.

scholarly journals Crystal symmetry determination in electron diffraction using machine learning

Science ◽  
2020 ◽  
Vol 367 (6477) ◽  
pp. 564-568 ◽  
Author(s):  
Kevin Kaufmann ◽  
Chaoyi Zhu ◽  
Alexander S. Rosengarten ◽  
Daniel Maryanovsky ◽  
Tyler J. Harrington ◽  
...  
Keyword(s):  
Machine Learning ◽  
Electron Backscatter Diffraction ◽  
Crystal Symmetry ◽  
Structure Identification ◽  
Phase Identification ◽  
Training Set ◽  
The Neural Network ◽  
Electron Backscatter ◽  
Diffraction Patterns ◽  
Backscatter Diffraction

Electron backscatter diffraction (EBSD) is one of the primary tools for crystal structure determination. However, this method requires human input to select potential phases for Hough-based or dictionary pattern matching and is not well suited for phase identification. Automated phase identification is the first step in making EBSD into a high-throughput technique. We used a machine learning–based approach and developed a general methodology for rapid and autonomous identification of the crystal symmetry from EBSD patterns. We evaluated our algorithm with diffraction patterns from materials outside the training set. The neural network assigned importance to the same symmetry features that a crystallographer would use for structure identification.

Phase Identification Using EBSD in the SEM: What Can be Done Today and What we Hope to do Tomorrow

1999 ◽  
Vol 5 (S2) ◽  
pp. 220-221
Author(s):  
J. R. Michael
Keyword(s):  
Fiber Optic ◽  
Electron Backscatter Diffraction ◽  
Phase Identification ◽  
Powder Diffraction File ◽  
Crystalline Materials ◽  
Future Developments ◽  
Electron Backscatter ◽  
Ebsd Pattern ◽  
Backscatter Diffraction

Phase identification using electron backscatter diffraction (EBSD) in the SEM has become a useful and important tool for the characterization of crystalline materials. Phase identification is accomplished using EBSD in the following manner. First, a high quality camera must be added to the SEM. Suitable cameras use slow scan CCD imagers coupled either by a lens or a fiber optic bundle to a phosphor screen that is situated near the sample. A EBSD pattern is collected and EDS or WDS is used to determine qualitatively the chemistry of the area. An automated routine is then used to extract the positions and widths of the lines in the pattern followed by a calculation of the unit cell volume. This information coupled with the chemistry of the sample is then used to search a database of crystal structures. Currently, the ICDD's Powder Diffraction file of over 100,000 compounds is used. Once a list of potential matches is found the patterns are indexed and then simulated to demonstrate that the phase has been identified. This paper will demonstrate use of EBSD for phase identification and then will speculate on future developments.A particularly nice application of EBSD is the use of the technique for the identification of phases that form in welds. Figure 1a is an EBSD pattern obtained from a acicular phase in a superalloy weld. The phase was determined to be primarily Ti and Ni. Analysis of the patterns showed that the phase is Ni3Ti. Figure 1b shows the simulation for Ni3Ti overlaid on the experimental pattern demonstrating that the phase has been identified.

Characterization of Ceramics Using Electron Backscatter Diffraction in the SEM

1999 ◽  
Vol 5 (S2) ◽  
pp. 794-795
Author(s):  
J.R. Michael
Keyword(s):  
Electron Backscatter Diffraction ◽  
Ccd Camera ◽  
Standard Technique ◽  
Ceramic Materials ◽  
Area Of Interest ◽  
Electron Backscatter ◽  
Characterization Of Materials ◽  
The Many ◽  
Backscatter Diffraction

The technique of electron backscatter diffraction (EBSD) in the scanning electron microscope is becoming a standard technique for the characterization of materials. EBSD has evolved into a tool that can determine the orientation of a crystalline area of interest or the technique can be used for the identification of unknown phases from their composition and crystallography. The application of the technique to ceramic materials has demonstrated the many advantages of this technique over classical x-ray diffraction techniques or electron diffraction in the TEM.EBSD patterns are obtained by illuminating a highly tilted sample (>45° from horizontal) with a stationary electron beam. Electrons that are backscattered from the sample may satisfy the condition for channeling (or diffraction) and produce images that contain bands of increased and decreased intensity that are equivalent to channeling patterns. The patterns are imaged by placing a phosphor screen near the sample and imaging the screen with either TV rate or a slow scan CCD camera.

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