High Resolution Microscopic Methods

Course type	lecture integrated learning activity
Information	LSF SEM laboratory at LMU
Responsible(s)	Prof. Dr. Claudia Trepmann Erika Griesshaber Prof. Dr. Wolfgang Schmahl
Eligible for	MSc Geomaterials and Geochemistry P 3.3 MSc Geology P 9.0.8, WP 5.0.4
Course location	Mineralogie, Theresienstr. 4
Date	SoSe
Course material	LSF

Course content

Microstructure is the link between science and technology of materials and is of major importance in material design and material processing technologies. Moreover, microstructure reconstruction is of fundamental significance in several Earth, biological and environmental science disciplines.

The microstructural characterization of a crystalline material includes the determination of grain number and size distribution, chemical composition, spatial distribution of phases, crystallographic and structural relationships between grains as well as intragranular misorientation. The analytical technique best suited for the quantitative microstructure and texture characterization of crystalline and crystal- bearing samples is EBSD (Electron Backscatter Diffraction) performed in a scanning electron microscope (SEM), and complemented by secondary electron (SE)-, backscattered electron (BSE)- and cathodoluminescence (CL)- imaging, scanning transmission electron microcopy (STEM) and phase identification with Energy Dispersive Spectroscopy (EDS). The thorough characterization of microstructure and texture provides basic information on the materials properties, such as anisotropy, strength and porosity, and on the formation processes resulting in the microfabric, such as deformation mechanisms, slip systems, mineral reactions, gas phase exsolution, as well as melting, diagenetic and metamorphic overprint.

This course will introduce the principles of quantitative microstructure and texture characterization of biological and geological materials (e.g., fossils, rocks) in a combination of lectures dealing with the topics listed below, hands-on exercises at the scanning electron microscope and data analysis using the AZtec software (Oxford instruments).

Topics include:

The scanning electron microscope: e.g. history, electron sources …
Interaction of incident electron beam with the sample: elastic/inelastic scattering, generation and detection of different signals as secondary electrons (SE) backscattered electons (BSE) and electron dispersive spectroscopy (EDS)
Electron backscattered diffraction, EBSD I: signal generation, backscattered Kikuchi pattern, Hough Transformation, indexing
Preparation techniques, chemo-mechanical polishing
EBSD II: Euler angles, band contrast, misorientation
EBSD III: Relative misorientation, misorientation angle distributions, grain boundaries
EBSD IV: pole figures, inverse pole figures, density plots, grain parameters, Schmid factor
Chemical analysis by energy dispersive spectroscopy (EDS), cathodoluminescence (CL)
General overview over transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM)

(information given by Prof. Dr. Trepmann, 2018)

Analytical methods

Literature

SEM

Goldstein, J., D.E. Newbury, D.C. Joy, C.E. Lyman, P. Echlin, E. Lifshin, L. Sawyer, and J.R. Michael: Scanning electron microscopy and X-ray microanalysis, Springer 2003.
W. Zhou, Z. L. Wang: Scanning electron microscopy for nanotechnology, Springer 2006.

EDS – EBSD

J. Schwartz, M. Kumar, B. L. Adams: Electron backscatter diffrection in materials science. Kluwer Academic Plenum Publishers 2000.
V. Randle, O. Engler: Introduction to texture analysis: Macrotexture, microtexture and orentation mapping. Harwood Academic 2000.
V. Randle: Microtexture determination and ist applications. IOM 1992.
F. J. Humphreys: Grain and subgrain characterisation by electron backscatter diffraction. J. Mat. Sci., 36, 3833-3854, 2001 (review).
D. Dingley: Progressive steps in the development of electron backscatter diffrection and orientation imaging microscopy. Journal of Microscopy, 213, 214.224, 2003.
D. J. Prior et al.: The application of electron backscatter diffraction and orientation contrast imaging in the SEM to textural problems in rocks. American Mineralogist, Volume 84, pages 1741–1759, 1999.
G. Seward, D. Prior, J. Wheeler et al. High-temperature electron backscatter diffraction and scanning electron microscopy imaging techniques: in-situ investigations of dynamic processes. Scanning, 24, 5, 2006.
S. Zaefferer: A critical review of orientation microscopy in SEM and TEM. Crystal Research and Technology, 46, 6, 607-628, 2011.
Wheeler, J., Prior, D., Jiang, Z., Spiess, R., Trimby, P., 2001. The petrological significance of misorientations between grains. Contrib. Mineral. Petrol. 141, 109-124.