MENA3100: Introduction to Microstructural Characterization and Crystallography

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

2. Student contact information MENA3100

3. Who is involved? • Anette E. Gunnæs: eleonora(at)fys.uio.no, 91514080 (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) • Sissel Jørgensen: sissel.jorgensen(at)kjemi.uio.no (SEM, 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

4. General information • Lectures • Based on “Microstructural characterization of materials” + by Brandon and Kaplan. SPM lecture based on chapter 7.8 in second edition of “Physical methods for materials characterisation” by Flewitt and Wild. EBSD will be based on separate text. • 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 (chapter 7 + some sub chapters). • 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

5. Laboratorygroups Laboratory work will mainly take place on Tuesdays. The trip to IFE, Kjeller has been rescheduled to Wednesday 13th of February! MENA3100

6. 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 Crunching etc…… What to learn about Different imaging modes. Mapping of elements or chemical states of elements. The same basic theory for all waves. MENA3100

7. Visible light Optical microscopy (OM) X-ray X-ray diffraction (XD) 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

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. c α b β γ a Basic aspects of crystallography • Crystallography describes and characterise the structure of crystals The unit cell ! Elementary unit of volume! - Defined by three non 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). MENA3100

12. c α b β γ a Unit cell • The crystal structure is described by specifying a repeating element and its translational periodicity • The repeating element (usually consisting of many atoms) is replaced by a lattice point and all lattice points have the same atomic environments. • The whole lattice can be described by repeating a unit cell in all three dimensions. The unit cells are the smallest building blocks. • A primitive unit cell has only one lattice point in the unit cell. Replaces repeating element (molecule, base etc.) MENA3100

13. z c α β y b γ a x Axial systems The point lattices can be described by 7 axial systems (coordinate systems) MENA3100

14. Bravais lattice The point lattices can be described by 14 different Bravais lattices Hermann and Mauguin symboler: P (primitiv) F (face centred) I (body centred) A, B, C (bace or end centred) R (rhombohedral) MENA3100

15. Hexagonal unit cell a1=a2=a3 γ = 120o a2 a1 a3 (hkil) h + k + i = 0 MENA3100

16. 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

17. 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

18. 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

19. Plots planes and directions in a 2D map Stereographic projection All poles in a zone are on the same great circle!! Fig 6.5 of Klein (2002) Manual of Mineral Science, John Wiley and Sons MENA3100

20. Wulff net Fig 6.8 of Klein (2002) Manual of Mineral Science, John Wiley and Sons MENA3100

21. 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