Abstract. Parallel electron energy-loss spectroscopy (PEELS) in a scanning transmission electron microscope (STEM) was used to record the Mn L2,3-edges from a range of natural and synthetic manganese containing materials, covering valences 0, II, III, IV and VII, with an energy resolution of ca. 0.5 eV. The Mn L2, 3 electron-loss near-edge structure (ELNES) of these edges provided a sensitive fingerprint of its valence. The Mn 2+ L2,3-edges show little sensitivity to the local site symmetry of the ligands surrounding the manganese. This is illustrated by comparing the Mn L2,3-edges from 4-, 6-and 8-fold coordinated Mn 2 § In contrast, the Mn L3-edges from Mn 3--and Mn 4+ containing minerals exhibited ELNES that are interpreted in terms of a crystal-field splitting of the 3d electrons, governed by the symmetry of the surrounding ligands. The Mn L3-edges for octahedrally coordinated Mn 2+, Mn 3+ and Mn 4+ showed variations in their ELNES that were sensitive to the crystal-field strength. The crystal-field strength (10Dq) was measured from these edges and compared very well with published optically determined values. The magnitude of 10Dq measured from the Mn L3-edges and their O K-edge prepeaks of the manganese oxides were almost identical. This further confirms that the value of 10Dq measured at the Mn L3-edge is correct. Selected spectra are compared with theoretical 2p atomic multiplet spectra and the differences and similarities are explained in terms of the covalency and site symmetry of the manganese. The Mn L3-edges allow the valence of the manganese to be ascertained, even in multivalent state materials, and can also be used to determine 10Dq.

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Observation of an unusual, negatively-charged antiphase boundary in (Bi0.85Nd0.15)(Ti0.1Fe0.9)O3 is reported. Aberration corrected scanning transmission electron microscopy is used to establish the full three dimensional structure of this boundary including O-ion positions to ∼±10 pm. The charged antiphase boundary stabilises tetragonally distorted regions with a strong polar ordering to either side of the boundary, with a characteristic length scale determined by the excess charge trapped at the boundary. Far away from the boundary the crystal relaxes into the well-known Nd-stabilised antiferroelectric phase

The evolution of precipitation and microstructure during a simulation of the thin slab direct rolling process, in six vanadium based, low carbon, steels with V, V-N, V-Ti-N, V-Nb, V-Nb-Ti and V-Zr additions was studied by optical microscopy, analytical transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDAX) and parallel electron energy loss spectroscopy (PEELS). Tensile properties and Charpy vee-notch toughness of the final strip were also determined. The effects of microalloying additions and processing conditions, including equalisation temperature (1 200°C, 1 100°C and 1 050°C) and end water cool temperature, on the austenite and ferrite grain sizes, as well as the type and composition of the precipitates, were determined. The relationship between the microstructure and the properties in the steels was also ascertained.

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Flame initiated (800 °C, 10 s) or bulk thermal (2 days, 1000 °C ) reactions of mixed powders of transition metal halides and CaC 2 or Al 4 C 3 produce transition metal carbides ( TiC, ZrC, HfC, V 8 C 7 , NbC, TaC, Cr 3 C 2 , Mo 2 C and WC ) in good yields. The carbides were characterised by X-ray powder diffraction, SEM/EDX, FTIR, microelemental analysis, TEM, electron diffraction and ELNES. bides exceeds 15000 tonnes annually.11 They are traditionally

The electron energy-loss near-edge structure ͑ELNES͒ at the O K edge has been studied in yttria-stabilized zirconia ͑YSZ͒. The electronic structure of YSZ for compositions between 3 and 15 mol % Y 2 O 3 has been computed using a pseudopotential-based technique to calculate the local relaxations near the O vacancies. The results showed phase transition from the tetragonal to cubic YSZ at 10 mol % of Y 2 O 3 , reproducing experimental observations. Using the relaxed defect geometry, calculation of the ELNES was carried out using the full-potential linear muffin-tin orbital method. The results show very good agreement with the experimental O K-edge signal, demonstrating the power of using ELNES to probe the stabilization mechanism in doped metal oxides.