1 / 29

MENA3100

MENA3100. 1 st lecture Øystein Prytz General information, what to learn and some repetition of crystallography. General information. Lectures Based on D. Brandon and W. D. Kaplan "Microstructural characterization of materials". Second edition, published by Wiley, 2008.

nbrister
Télécharger la présentation

MENA3100

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. MENA3100 1st lecture Øystein Prytz General information, what to learn and some repetition of crystallography MENA3100

  2. General information • Lectures • Based on D. Brandon and W. D. Kaplan "Microstructural characterization of materials". Second edition, published by Wiley, 2008. • Some parts of the Brandon and Kaplan book will be regarded as self study material and other parts will be taken out of the curriculum. • Project work • Energy related projects will be announced by the end of January • Two students will work together, rank projects with 1st-3rd priority • Written report, oral presentation and individual examination • Counts 40 % of final grade • Laboratories • Three groups: A, B, C • Individual reports • All reports have to be evaluated and found ok before final written exam MENA3100

  3. Imaging/microscopy Optical Electron SEM TEM Scanning probe AFM STM Diffraction X-rays Electrons ED in TEM and EBSD in SEM Neutrons Spectroscopy EDS X-rays EELS Electrons XPS, AES Electrons (surface) SIMS Ions Sample preparation Mechanical grinding/polishing Chemical polishing/etching Ion bombardment Crushing etc…… What to learn about Different imaging modes. Mapping of elements or chemical states of elements. The same basic theory for all waves. MENA3100

  4. Visible light Optical microscopy (OM) X-ray X-ray diffraction (XRD) X-ray photo electron spectroscopy (XPS) Neutron Neutron diffraction (ND) Ion Secondary ion mass spectrometry (SIMS) Cleaning and thinning samples Electron Scanning electron microscopy (SEM) Transmission electron microscopy (TEM) Electron holography (EH) Electron diffraction (ED) Electron energy loss spectroscopy (EELS) Energy dispersive x-ray spectroscopy (EDS) Auger electron spectroscopy (AES) Probes used MENA3100

  5. Who is involved? • Øystein Prytz: oystein.prytz (at)fys.uio.no, 93201512 (General, TEM, ED) • Johan Taftø: johan.tafto(at)fys.uio.no (waves optics, TEM, EELS) • Ole Bjørn Karlsen: obkarlsen(at)fys.uio.no (OM, XRD) • Harald Fjeld: harald.fjeld(at)smn.uio.no (SEM) • Anders Skilbred: awlarsen(at)ifi.uio.no (SEM) • Sissel Jørgensen: sissel.jorgensen(at)kjemi.uio.no (EDS, XPS) • Spyros Diplas: spyros.diplas(at)smn.uio.no (XPS) • Lasse Vines: Lasse.vines(at)fys.uio.no (SIMS) • Terje Finnstad: terje.finnstad(at)fys.uio.no (SPM) • Oddvar Dyrlie: oddvar.dyrlie(at)kjemi.uio.no (SPM) • Magnus Sørby: magnus.sorby(at)IFE.no (ND) • Geir Helgesen: geir.helgesen(at)IFE.no (ND) MENA3100

  6. Student contact information MENA3100

  7. Laboratorygroups Laboratoratory work is mandatory! The trip to IFE, Kjeller is planned for Wednesday 11th of February! MENA3100

  8. Valence M 3d6 M 3p4 L 3d4 3s2 2p4 3p2 K Electron shell 2s2 2p2 1s2 L K Basic principles, electron probe Electron Auger electron or x-ray Characteristic x-ray emitted or Auger electron ejected after relaxation of inner state. Low energy photons (cathodoluminescence) when relaxation of outer stat. Secondary electron MENA3100

  9. Valence M Electron shell L K Basic principles, x-ray probe X-ray Auger electron Secondary x-rays M L K Characteristic x-ray emitted or Auger electron ejected after relaxation of inner state. Low energy photons (cathodoluminescence) when relaxation of outer stat. Photo electron MENA3100

  10. Basic principles X-rays Electrons Ions (SEM) (XD) X-rays X-rays (EDS) (XPS) BSE Ions (SIMS) PE AE SE AE (Also used for cleaning/thinning samples) You will learn about: - the equipment -imaging -diffraction -the probability for different events to happen -energy related effects -element related effects -etc., etc., etc…….. SE E<Eo (EELS) E=Eo (TEM and ED) MENA3100

  11. Introduction to crystallography We divide materials into two categories: • Amorphous materials • The atoms are ”randomly” distributed in space • Not quite true, there is short range order • Examples: glass, polystyrene (isopor) • Crystalline materials • The atoms are perfectly ordered • Short range and long range order • Deviations from the perfect order are important MENA3100

  12. Introduction to crystallography MENA3100

  13. Introduction to crystallography Scattering angle 2Theta MENA3100

  14. Introduction to crystallography MENA3100

  15. Introduction to crystallography MENA3100

  16. Basic aspects of crystallography • Crystallography describes and characterise the structure of crystals • Basic concept is symmetry • Translational symmetry: if you are standing at one point in a crystal, and move a distance (vector) a the crystal will look exactly the same as where you started. a a a a MENA3100

  17. The lattice • In the previous example we had a group of atoms that was repeated in (1D) space • This can be described as a set of mathematical points in space called the lattice • In each of these points we put a group of atoms, the basis Basis + Lattice = crystal structure a a a a a a MENA3100

  18. The Bravais lattices • In dealing with crystals we use lattices in three dimensions • It can be shown that 14 different types of lattices are needed to describe all crystalline arrangements of atoms in space • These are the Bravais lattices • They are classed in terms of the vectors a, b and c, or rather their lengths a, b and c, and angle between them ,  and  • Seven crystal systems: Cubic, Tetragonal, Orthorhombic, Rhombohedral, Hexagonal, Monoclinic, Triclinic MENA3100

  19. Bravais lattices Seven crystal systems: Cubic Tetragonal Orthorhombic Rhombohedral Hexagonal Monoclinic Triclinic Lattice centering (Hermann-Mauguin symbols): P (primitive) F (face centered) I (body centred) A, B, C (base or end centered) R (rhombohedral) MENA3100

  20. Exaples of materials with a face centered cubic lattice Copper MENA3100

  21. Exaples of materials with a face centered cubic lattice Silicon MENA3100

  22. Exaples of materials with a face centered cubic lattice ZnS MENA3100

  23. What about other symmetry elements? • We have discussed translational symmetry, but there are also other important symmetry operations: • Mirror planes • Rotation axes • Inversion • Screw axes • Glide planes • The combination of these symmetry operations with the Bravais lattices give the 230 space groups MENA3100

  24. Mirror planes and rotation axes, a 2D example • Imagine a 2D rectangular centered lattice • Basis number 1: atom in (0,0) relative to each lattice point • Basis number 2: atoms in (0,0) and (1/4,1/4) relative to each lattice point Lattice: Lattice + basis What mirror planes and rotation axes are present in the two cases? MENA3100

  25. c α b β γ a The unit cell • Elementary unit of volume! - Defined by three non co-planar lattice vectors: a, b and c -The unit cell can also be described by the length of the vectors a,b and c and the angles between them (alpha, beta, gamma). - The unit cell is the smallest unit of volume in the material that contains all the symmetry elements characteristic of the crystal structure The unit cell ! MENA3100

  26. Crystals can be classified according to 230 space groups. Details about crystal description can be found in International Tables for Crystallography. Criteria for filling Bravais point lattice with atoms. Both paper books and online Space groups • A space group can be referred to by a number or the space group symbol (ex. Fm-3m is nr. 225) • Structural data for known crystalline phases are available in books like “Pearson’s handbook of crystallographic data….” but also electronically in databases like “Find it”. • Pearson symbol like cF4 indicate the axial system (cubic), centering of the lattice (face) and number of atoms in the unit cell of a phase (like Cu). MENA3100 Figur: M.A. White: Properties of Materials

  27. z (001) (111) (110) (010) Z Z Z c/l b/k a/h (100) 0 y x Y Y Y X X X Lattice planes • Miller indexing system • Crystals are described in the axial system of their unit cell • Miller indices (hkl) of a plane is found from the interception of the plane with the unit cell axis (a/h, b/k, c/l). • The reciprocal of the interceptions are rationalized if necessary to avoid fraction numbers of (h k l) and 1/∞ = 0 • Planes are often described by their normal • (hkl) one single set of parallel planes • {hkl} equivalent planes MENA3100

  28. The indices of directions (u, v and w) can be found from the components of the vector in the axial system a, b, c. The indices are scaled so that all are integers and as small as possible Notation [uvw] one single direction or zone axis <uvw> geometrical equivalent directions [hkl] is normal to the (hkl) plane in cubic axial systems z wc [uvw] Zone axis [uvw] c b a vb ua y x Directions (hkl) uh+vk+wl= 0 MENA3100

  29. Reciprocal vectors, planar distances • The normal of a plane is given by the vector: • Planar distance between the planes {hkl} is given by: • The reciprocal lattice is defined by the vectors : • Planar distance (d-value) between planes {hkl} in a cubic crystal with lattice parameter a: MENA3100

More Related