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Research subject. The Savabeisky sulfide copper-nickel ore occurrence, located in the central part of the Khengur (Central Pay-Khoy) gabbro-dolerite complex of the Pay-Khoy, within the Yugorsky Peninsula, located in the Far North-East of the European part of Russia, in the Arkhangelsk region, between the Barents and Kara Seas.Materials and methods. Samples of copper-nickel ores with noble metal mineralization were studied. Palladium tellurides and bismuthtellurides were characterized using optical and scanning electron microscopy, electron backscatter diffraction (EBSD), X-ray structural analysis and Raman spectroscopy.Results. Bismuthtellurides in the Paykhoysko-Vaigach-Yuzhnonovozemelskiy region – michenerite, merenskyite and unidentified palladium telluride of the kotulskite–merenskyite series with crystal formula Pd2(TeSbBi)3 – were found for the first time. The unit cell parameter of Pay-Khoy michenerite was calculated using X-ray diffraction analysis data: a = 6.638(2) Å. According to Raman spectroscopy, the palladium tellurides and bismuthtellurides of the Savabeisky ore occurrence were distinguished into 4 groups: Sb-kotulskite (does not contain Raman-active modes), unnamed PGM Pd2(TeSbBi)3 (bands in the range 95–103, 121–126 cm–1, obtained for the first time), Sb-merenskyite (band 126–135 cm–1), michenerite (bands with maxima 100 and 116 cm–1, obtained for the first time). The Kikuchi lines for michenerite and the mineral of the kotulskite–merenskyite series were obtained by the EBSD method.Conclusions. The diagnosis of palladium tellurides and bismuthtellurides is a rather complicated problem (wide variations in compositions, low hardness, small size, thin intergrowths of several individuals, the presence of impurities, etc.) affecting the determination of their mineral form and requiring an integrated approach. The Raman spectra of michenerite and unnamed PGM can be used as standards for the rapid identification of their natural forms, in contrast to EBSD, which requires improved sample preparation. The relatively high content of antimony in the ore minerals and noble metals minerals at the Savabeisky ore occurrence is the antimony metallogenic specificity characteristic of the entire Uralsko-Novozemelskiy province.

Two advanced, automated crystal orientation mapping techniques suited for nanocrystalline materials—precession electron diffraction (PED) in transmission electron microscopy (TEM) and on-axis transmission Kikuchi diffraction (TKD) in scanning electron microscopy (SEM)—are evaluated by comparing the orientation maps obtained from the identical location on a 30 nm-thick nanocrystalline tungsten (W) thin film. A side-by-side comparison of the orientation maps directly showed that the large-scale orientation features are almost identical. However, there are differences in the fine details, which arise from the fundamentally different nature of the spot pattern and Kikuchi line pattern in terms of the excitation volume and the angular resolution. While TEM-PED is more reliable to characterize grains oriented along low-index zone axes, the high angular resolution of SEM-TKD allows the detection of small misorientation between grains and thus yields better quantification and statistical analysis of grain orientation. Given that both TEM-PED and SEM-TKD orientation mapping techniques are complementary tools for nanocrystalline materials, one can be favorably selected depending on the requirements of the analysis, as they have competitive performance in terms of angular resolution and texture quantification.

We discuss a refined simulation approach which treats Kikuchi diffraction patterns in electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD). The model considers the result of two combined mechanisms: (a) the dynamical diffraction of electrons emitted coherently from point sources in a crystal and (b) diffraction effects on incoherent diffuse intensity distributions. Using suitable parameter settings, the refined simulation model allows to reproduce various thickness- and energy-dependent features which are observed in experimental Kikuchi diffraction patterns. Excess-deficiency features are treated by the effect of gradients in the incoherent background intensity. Based on the analytical two-beam approximation to dynamical electron diffraction, a phenomenological model of excess-deficiency features is derived, which can be used for pattern matching applications. The model allows to approximate the effect of the incident beam geometry as a correction signal for template patterns which can be reprojected from pre-calculated reference data. As an application, we find that the accuracy of fitted projection centre coordinates in EBSD and TKD can be affected by changes in the order of 10-3 - 10-2 if excess-deficiency features are not considered in the theoretical model underlying a best-fit pattern matching approach. Correspondingly, the absolute accuracy of simulation-based EBSD strain determination can suffer from biases of a similar order of magnitude if excess-deficiency effects are neglected in the simulation model.

In this study, electron diffraction patterns observed under high vacuum conditions for an SrTiO3 surface were interpreted in detail while paying special attention to the features of inelastic effects. The surface of the SrTiO2 was carefully prepared to enforce its termination with single domains of TiO2 layers at the top. The inelastic patterns were interpreted using analytical models. Two types of Kikuchi lines are recognized in this paper: those which can be described with the Bragg law and those which appear due to surface wave resonance effects. However, we also discuss that there exists a formal connection between the two types of the Kikuchi lines observed.

In this study, a new method is established for indexing electron backscatter diffraction (EBSD) patterns assisted by the Kikuchi bandwidth. This method utilises both interplanar angles and interplanar spacings to determine the Miller indices of the Kikuchi bands in EBSD patterns to improve the efficiency and precision of indexing in the EBSD system. Two samples of single-crystal silicon were investigated to validate the method based on (a) the detection of the edges of the EBSD Kikuchi bands and (b) the calculation of the Kikuchi bandwidths. The relationship between the Kikuchi bandwidth and the interplanar spacing at different positions was established, and the interplanar spacing of the corresponding lattice plane of each Kikuchi band was calculated with the use of the Kikuchi bandwidth information. The relative errors between the theoretical and experimental interplanar spacings are small, with an average relative error of 2.6% and a minimum relative error of 1.04%. The results indicated that the Miller index of each Kikuchi band can be determined accurately with this new method. It is demonstrated that use of this new method improves the efficiency and accuracy of the EBSD system. LAY DESCRIPTION: Electron backscatter diffraction (EBSD) is a scanning electron microscope-based technique. In our work, a new method is established for indexing EBSD patterns assisted by the Kikuchi bandwidth. This method utilizes both interplanar angles and interplanar spacings to determine the Miller indices of the Kikuchi bands in EBSD patterns to improve the efficiency and precision of indexing in the EBSD system. Two samples of single-crystal silicon were investigated to validate the method based on a) the detection of the edges of the EBSD Kikuchi bands and b) the calculation of the Kikuchi bandwidths. The relationship between the Kikuchi bandwidth and the interplanar spacing at different positions was established, and the interplanar spacing of the corresponding lattice plane of each Kikuchi band was calculated with the use of the Kikuchi bandwidth information. The relative errors between the theoretical and experimental interplanar spacings are small, with an average relative error of 2.6% and a minimum relative error of 1.04%. Compared with the results reported in the literature, the width-assisted Kikuchi pattern indexing method can well distinguish some cases with similar angles, and reduce the possibility of mis-indexing. After the introduction of the width information of the Kikuchi bands, the screening range can be narrowed by determining the crystal plane family, and the efficiency and accuracy of the indexing process can thus be improved. Specifically, for some materials with increased symmetry, such as cubic crystal materials, it is necessary to use the interplanar spacing for indexing when the interplanar angles are not diagnostic. The results indicated that the Miller index of each Kikuchi band can be determined accurately with this new method. It is demonstrated that use of this new method improves the efficiency and accuracy of the EBSD system.

The necessary parameters (rotation axis, incident electron beam direction and beam tilt path) in order to describe the diffraction geometry in the Rotation Electron Diffraction (RED) method during data collection are determined and refined. These parameters are prerequisites for the subsequent calculations of excitation errors, sg, for zero (ZOLZ) or higher order Laue zones (HOLZ) reflections. Comparison with simulated results, for a CoP3 thermoelectric crystal, shows excellent agreement between the two approaches -calculated and simulated. In addition to their determination, a thorough refinement methodology for the incident electron beam direction and beam tilt path has been applied, too, based on Kikuchi lines of HOLZ reflections. Incorporation of the refined excitation error values can be considered both in theoretical calculations for diffracted beam intensities, based on the Bloch wave method, as well as in deducing integrated intensities from experimental rocking curves. The methodology described in this study is quite indispensable, as it forms an essential step for performing dynamical calculations in RED, enabling thus enhanced accuracy in structural parameter clarification. The latter is especially important in the case of thermal factors refinement for e.g. thermoelectrics, which are imperative for material properties’ evaluation.

International audience; EBSD analysis can provide information about grain orientation, texture and grain boundary misorientation of bulk superconducting MgB2 samples intended for supermagnet applications. However, as the grain size of the MgB2 bulks is preferably in the 100–200 nm range, the common EBSD technique operating in reflection mode works only properly on highly dense samples. In order to achieve reasonably good Kikuchi pattern quality on all types of MgB2 samples, we apply here the newly developed transmission EBSD (t-EBSD) technique to spark-plasma sintered MgB2 samples. This method requires the preparation of TEM slices by means of focused ion-beam milling, which are then analysed within the SEM, operating with a custom-built sample holder. To obtain multiphase scans, we identified the Kikuchi pattern of the MgB4 phase which appears at higher reaction temperatures and may act as additional flux pinning sites. We present here for the first time EBSD mappings of multiple phases, which include MgB2, MgB4 and MgO. Lay Description The electron backscatt er diffraction (EBSD) technique operating in the scanning electron microscope provides information on the crystallographic orientation the material by recording Kikuchi patterns. In polycrystalline samples, it becomes possible to analyse the orientations of the grains to each other. The metallic superconductor with the currently highest superconducting transition temperature, MgB2 with a Tc of 38.5 K, can be used in applications in polycrystalline form. One such application of interest are trapped field magnets or supermagnets, where the superconductor cooled in an applied magnetic field can trap the magnetic field as vortices at numerous flux pinning sites in the sample. When the external magnetic field is removed, the sample will stay magnetised as long as it is kept cool, and importantly, the trapped magnetic fields can be much higher as for any permanent magnet. However, the small size of the MgB2 grains in the 100–200 nanometre range requires a different approach when using the EBSD technique on such samples. The recently developed EBSD technique working in transmission mode (t-EBSD) helps considerably to image such materials. In this approach, a tiny TEM slice has to be milled out from the original sample by using focused ion beam milling. To understand the properties of the flux pinning in the spark-plasma sintered MgB2 sample, we had to identify the Kikuchi pattern of MgB4, which is another, non-superconducting phase appearing at higher reaction temperatures required to compact the material. Using this information, we could perform EBSD scans using three different phases, MgB2, MgB4 and MgO. The EBSD mappings enable to see where the secondary phase particles are located in the sample, and to judge if the particles could work as flux pinning sites. © 2019 The Authors Journal of Microscopy © 2019 Royal Microscopical Society

A new software is presented for the determination of crystal lattice parameters from the positions and widths of Kikuchi bands in a diffraction pattern. Starting with a single wide‐angle Kikuchi pattern of arbitrary resolution and unknown phase, the traces of all visibly diffracting lattice planes are manually derived from four initial Kikuchi band traces via an intuitive graphical user interface. A single Kikuchi bandwidth is then used as reference to scale all reciprocal lattice point distances. Kikuchi band detection, via a filtered Funk transformation, and simultaneous display of the band intensity profile helps users to select band positions and widths. Bandwidths are calculated using the first derivative of the band profiles as excess‐deficiency effects have minimal influence. From the reciprocal lattice, the metrics of possible Bravais lattice types are derived for all crystal systems. The measured lattice parameters achieve a precision of, New software and algorithms for the accurate measurement of crystal lattice parameters from Kikuchi bands in a diffraction pattern are presented. image

Symmetry analysis of the Kikuchi pattern is helpful to determine the crystal structure, and can significantly reduce the screening range of phase identification, thereby improving the accuracy and reliability of phase identification in electron backscatter diffraction (EBSD). Accurately identifying the symmetry axis from the Kikuchi pattern is the primary task of symmetry analysis. In this study, a new method was proposed to identify symmetry axes in Kikuchi patterns with the aid of reciprocal vectors. Taking the Kikuchi patterns of single-crystal silicon as a typical example, a method for drawing reciprocal vectors after strict projection correction is introduced. The complex task of identifying the symmetry axis is transformed into an intuitive judgment of the geometric relationship between reciprocal vectors, thus greatly simplifying the process. This method successfully elucidated information on six Kikuchi poles in three single-crystal silicon Kikuchi patterns, including 3-fold axes, 4-fold axes and asymmetric axes. The method can also distinguish between a 3-fold axis and an analogous 3-fold axis despite their only slight differences.Symmetry analysis of the Kikuchi pattern is helpful to determine the crystal structure, and can significantly reduce the screening range of phase identification, thereby improving the accuracy and reliability of phase identification in electron backscatter diffraction (EBSD). Accurately identifying the symmetry axis from the Kikuchi pattern is the primary task of symmetry analysis. In our study, a new method was proposed to identify symmetry axes in Kikuchi patterns with the aid of reciprocal vectors. Taking the Kikuchi patterns of single-crystal silicon as a typical example, a method for drawing reciprocal vectors after strict projection correction is introduced. The complex task of identifying the symmetry axis is transformed into an intuitive judgment of the geometric relationship between reciprocal vectors, thus greatly simplifying the process. This method successfully elucidated information on six Kikuchi poles in three single-crystal silicon Kikuchi patterns, including 3-fold axes, 4-fold axes and asymmetric axes. The method can also distinguish between a 3-fold axis and an analogous 3-fold axis despite their only slight differences. It is indicated that the reciprocal vectors after projection correction can reflect the symmetry information well, making the identification of the symmetry axis more intuitive, which is helpful for symmetry analysis of the Kikuchi pattern, and lays an important foundation for phase identification using crystal symmetry.

Enantiomorph-distribution maps for chiral element and multicomponent structures by Electron Backscatter Diffraction., The assignment of enantiomorphs by diffraction methods shows fundamental differences for x-rays and electrons. This is particularly evident for the chiral allotrope of β-Mn. While it is not possible to determine the sense of chirality of β-Mn with established x-ray diffraction methods, Kikuchi pattern simulation of the enantiomorphs reveals differences, if dynamical electron diffraction is considered. Quantitative comparison between experimental and simulated Kikuchi patterns allows the spatially resolved assignment of the enantiomorph in polycrystalline materials of β-Mn, as well as the structurally strongly related phase Pt2Cu3B. On the basis of enantiomorph distribution maps, crystals were extracted from enantiopure domains by micropreparation techniques. The x-ray diffraction analyses confirm the assignment of the Kikuchi pattern evaluations for Pt2Cu3B and do not allow to distinguish between the enantiomorphs of β-Mn.

The paper presents the structural characterization of &gamma, &prime, Fe4N nitrides produced by active screen plasma nitriding (ASPN) processes. Experiments were performed on the Fe-Armco model material at 693, 773, and 853 K for 6 h. Investigation of the properties of the substrate was realized using scanning electron microscopy (SEM, SEM&ndash, EBSD/Kikuchi lines), energy-filtered transmission electron microscopy (TEM-EFTEM), X-ray diffraction (GID, grazing incidence diffraction, micro-XRD), and secondary ion mass spectroscopy (SIMS). Results have confirmed that the &gamma, Fe4N nitrides&rsquo, structure and morphology depend considerably on the nitriding process&rsquo, s plasma conditions and cooling rate. In addition to that, &gamma, formation can be correlated with the surface layer saturation mechanism and recombination effect. It has been shown that the &gamma, Fe4N structure depends considerably on several phenomena that occur in the diffusive layer (e.g., top layer decomposition, nitrogen, and carbon atoms&rsquo, migration). Our research proves that the nitrogen concentration gradient is a driving force of nitrogen migration atoms during the recombination of &gamma, Fe4N nitrides. Finally, realized processes have allowed us to optimize active screen plasma nitriding to produce a surface layer of fine nitrides.

The destabilization problem is of importance in the application of yttria-stabilized zirconia (YSZ) bio-ceramic in the oral environment due to phase transformation between tetragonal to monoclinic. Thus, in this study, the lattice distortion induced by hydrothermal aging in yttria-stabilized zirconia (YSZ) was investigated, in which YSZ specimens were subjected to hydrothermal-aging treatment for 0–48 h. The Kikuchi-band based method was employed to calculate the lattice distortion after phase transformation and the results from EBSD were compared with these obtained by X-ray diffraction (XRD). Both measurement methods showed a similar tendency of the lattice change in the a- and c- axes. EBSD results showed that the strain rates were 7.98 % and −5.03 % at the a- and c-axes, respectively. A significant decrease in the c/a ratio from 1.429 to 1.257 for the tetragonal matrix after 48 h aging is observed, which indicated Kikuchi-band based method using EBSD technique can successfully determine the local strain in tetragonal matrices.

Dislocation is the most important defect of modern engineering materials involving structural and electronic application. Proper operation and understanding of dislocation also serve the basis for other characterization work. This paper deals with both underlying principles and practical aspects of dislocation characterization. Thin foil of electronic grade Cu is loaded into a double tilt specimen holder of Analytical TEM, JEOL JEM 1200EX. [001] Low Index Zone Axis was located with the aid of Kikuchi Lines. Two-Beam Condition was achieved for [200] [220] g vector. Bright Field and Dark Field Image of the Dislocation and their related Diffraction Patterns were taken at the Sample Edge. Dark field weak beam imaging has advantages in the accurate characterization of dislocations since the images produced by this technique meet all basic requirements for dislocation study.

The microstructure and chemical composition of a 316L stainless steel prepared by selective laser melting have been characterized using electron backscatter diffraction, transmission electron microscopy and atom probe tomography (APT). A multi-scale microstructure in the 316L stainless steel was observed in the as-built samples, consisting of equiaxed and columnar grains, dislocation cell blocks, dislocation cells, individual dislocations and nano-sized particles. The misorientations across the dislocation cells were determined based on local crystallographic orientation measurements using a Kikuchi pattern method. The dislocation cells have very small misorientation angles, with an average angle of 0.9°, and are arranged to form dislocation cell-blocks, with cell-block boundary misorientation angles generally larger than 2°. The APT data reveal that alloying elements are evenly distributed in the matrix as well as a high nitrogen content in the as-built material. Based on quantification of the microstructural parameters, good agreement is found between the yield strength as calculated from a linear sum of different strengthening contributions, and the experimentally measured value, with significant contributions both from dislocation strengthening and solid solution strengthening effects.

The Bravais lattices and their lattice parameters are blindly determined using electron backscatter diffraction (EBSD) patterns of materials with cubic or tetragonal crystal structures. Since the geometric relationships in a single EBSD pattern are overdetermined, the relative errors of determining the lattice parameters as well as the axial ratios are confined to about 0.7 ± 0.4% and 0.07 ± 0.03%, respectively, for ideal simulated EBSD patterns. The accuracy of the crystal orientation determination reaches about 0.06 ± 0.03°. With careful manual band detection, the accuracy of determining lattice parameters from experimental patterns can be as good as from simulated patterns, although the results from simulated patterns are often better than expermental patterns, which are lower quality and contain uncertain systematic errors. The reasonably high accuracy is obtained primarily because the detection of the diffracting-plane traces and zone axes is relatively accurate. The results here demonstrate that the developed procedure based on the EBSD technique presents a reliable tool for crystallographic characterization of the Bravais lattices of unknown phases.

Graphical abstract, One of the limitations of atomistic simulations is that many of the computational tools used to extract structural information from atomic trajectories provide metrics that are not directly compatible with experiments for validation. In this work, to bridge between simulation and experiment, a method is presented to produce simulated Kikuchi diffraction patterns using data from atomistic simulations, without requiring a priori specification of the crystal structure or defect periodicity. The Kikuchi pattern simulation is based on the kinematic theory of diffraction, with Kikuchi line intensities computed via a discrete structure factor calculation. Reciprocal lattice points are mapped to Kikuchi lines using a geometric projection of the reciprocal space data. This method is validated using single crystal atomistic models, and the novelty of this approach is emphasized by simulating kinematic Kikuchi diffraction patterns from an atomistic model containing a nanoscale dislocation loop. Deviations in kinematic Kikuchi line intensities are explained considering the displacement field of the dislocation loop, as is done in diffraction contrast theory.

A novel intermetallic Mg7Ag3 phase in the Mg–Ag binary alloy system at 573 and 623 K was discovered by the diffusion couple technique combined with the equilibrated alloy method. The composition and crystal structure of the Mg7Ag3 phase were identified via scanning electron microscopy/energy dispersive spectrometry, X-ray diffractometry (XRD), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The refinement of the XRD patterns was performed by Rietveld analysis. The XRD data have shown that Mg7Ag3 crystallizes in a body-centered crystal structure with Immm/orthorhombic symmetry (space group No. 71) and lattice parameters a = 14.2172, b = 14.6184, c = 14.177 Å and α = 90°. The well indexed selected area electron diffraction patterns and Kikuchi pattern obtained from TEM and EBSD confirmed the crystallographic structure obtained by XRD.

In this paper an alternative method of off-line Kikuchi pattern centre calibration and orientation mapping, utilising the cross-correlation between entire experimental patterns and dynamical simulated patterns is applied and evaluated. To demonstrate the improvement in angular resolution compared to Hough transform based methods, EBSD datasets of a silicon monocrystal were analysed using both, classical and the presented cross-correlation based method, which revealed significant enhancement of angular resolution for the refined method. The mean misorientation over the monocrystalline sample was found to be up to one order of magnitude lower compared to common methods, with an angular resolution of up to 0.06° indicating a substantial gain in orientation precision. The pattern centres were determined for a number of patterns on the map, using pattern matching refinement as well. Subsequently, a multiple linear regression model was computed to correlate pattern centre positions (XPC, YPC) and detector distances (ZSSD) to x- and y-coordinates on the map by means of plane equations. Employing this method, a reduction of orientation noise was achieved in highly deformed Silicon crystals with large intragranular orientation ranges. Furthermore, it was shown that the cross correlation coefficient CC can be used as a parameter indicating the pattern quality and hence can be utilised to create a pseudo greyscale image of the surface, showing grain boundaries and also depicting lattice distortions.

Automated orientation mapping in SEM, until now relying on EBSD solely, is currently being improved with the development of the TKD technique. As part of the development of TKD, we introduce a new, TEM-like geometric configuration, with a detector "on-axis" relative to the electron beam, while the detector was "off-axis" in its first form. This new technique produces a wide range of diffraction contrast (spots, lines, bands), varying with sample thickness, incident energy, atomic number and scattering angle. Some of the main trends are identified and discussed. In particular, a model based on the plasmon and phonon scattering is proposed to account for the disappearing of diffraction spots with thickness and incident energy. This work should help experimentalists determine which microscope and sample parameters to use in order to obtain a specific contrast. Finally, the strength and weakness of each diffraction feature for orientation mapping are also reviewed.

Correlative microscopy approaches offer synergistic solutions to many research problems. One such combination, that has been studied in limited detail, is the use of atom probe tomography (APT) and transmission Kikuchi diffraction (TKD) on the same tip specimen. By combining these two powerful microscopy techniques, the microstructure of important engineering alloys can be studied in greater detail. For the first time, the accuracy of crystallographic measurements made using APT will be independently verified using TKD. Experimental data from two atom probe tips, one a nanocrystalline Al–0.5Ag alloy specimen collected on a straight flight-path atom probe and the other a high purity Mo specimen collected on a reflectron-fitted instrument, will be compared. We find that the average minimum misorientation angle, calculated from calibrated atom probe reconstructions with two different pole combinations, deviate 0.7° and 1.4°, respectively, from the TKD results. The type of atom probe and experimental conditions appear to have some impact on this accuracy and the reconstruction and measurement procedures are likely to contribute further to degradation in angular resolution. The challenges and implications of this correlative approach will also be discussed.

Convergent-beam electron diffraction (CBED) is one of the most popular techniques to measure crystal thickness. The traditional measurement involves linear fitting of several fringes across the CBED disc, but for a thin crystal with fewer than three fringes the usefulness of this method will be limited. CBED Tools, a free plugin for the DigitalMicrograph software, provides a fast (∼1–2 min) and accurate algorithm to measure the crystal thickness on the basis of the linear fitting method, but it is also capable of determining the crystal thickness when it is very thin and only one fringe or part of the first fringe is recorded. CBED Tools can also be utilized to handle the severely distorted CBED pattern obtained when the zero-order Laue zone Kikuchi lines overlap with the fringes.

Kikuchi diffraction patterns can provide fundamental information about the lattice metric of a crystalline phase. In order to improve the possible precision and accuracy of lattice parameter determination from the features observed in Kikuchi patterns, some useful fundamental relationships of geometric crystallography are reviewed, which hold true independently of the actual crystal symmetry. The Kikuchi band positions and intersections and the Kikuchi band widths are highly interrelated, which is illustrated by the fact that all lattice plane trace positions of the crystal are predetermined by the definition of only four traces. If, additionally, the projection centre of the gnomonic projection is known, the lattice parameter ratios and the angles between the basis vectors are fixed. A further definition of one specific Kikuchi band width is sufficient to set the absolute sizes of all lattice parameters and to predict the widths of all Kikuchi bands. The mathematical properties of the gnomonic projection turn out to be central to an improved interpretation of Kikuchi pattern data, emphasizing the importance of the exact knowledge of the projection centre.

Angle-resolved electron Rutherford backscattering (ERBS) measurements using an electrostatic electron energy analyser can provide unique access to element-resolved crystallographic information. We present Kikuchi pattern measurements of the non-centrosymmetric crystal GaP, separately resolving the contributions of electrons backscattered from Ga and P. In comparison to element-integrated measurements like in the method of electron backscatter diffraction (EBSD), the effect of the absence of a proper 4-fold rotation axis in the point group of GaP can be sensed with a much higher visibility via the element-resolved Ga to P intensity ratio. These element-resolved measurements make it possible to experimentally attribute the previously observed point-group dependent effect in element-integrated EBSD measurements to the larger contribution of electrons scattered from Ga compared to P.

Electron backscatter diffraction (EBSD) device can provide crystal structure, orientation, and phase content data through analysis of EBSD patterns. The reliability and precision of these data depend on the quality of the band position and zone axes data. This study introduces a new image processing method that can accurately provide the location of Kikuchi bands and poles. In this method, pattern rotation and gray gradient calculation are employed after for the initial detection of Kikuchi lines. Hough transform and Gaussian function are used for the final definition of bands position. Based on the position of Kikuchi bands, the indices of lattice planes and zone axes can be obtained precisely and easily. Angles between zone axes are calculated using locating results. The maximum error for a single-crystal silicon sample is only 8.07%, illustrating the accuracy of this new method.

An 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.