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Electronic Microscopy and Material Microanalysis

Research Area: 
Physical Sciences
Engineering & Technology
Location: 

University of the basque country UPV/EHUScience and technology faculty Edificio CD3Rosalind Franklin research bulidingBº Sarriena s/n 48940 Leioa (Bizkaia)

Contact: 

Dr. Sergio Fernández Phone: 94 601 5998 E-mail: sergio.fernandez@ehu.esDr. Ana Martínez Amesti Phone: 94 601 5106 E-mail: ana.martinez@ehu.esDr. Mariano Barrado Phone: 94 601 8261 E-mail: mariano.barrado@ehu.es

Available for external users?: 
Yes
Access protocol: 

Access to the unit of Electronic Microscopy and Material Microanalysis involves meeting the requirements set forth in the Protocol for access to SGIker and the services it provides.

Description: 

The Electronic Microscopy and Material Microanalysis Service is equipped with a suitable infrastructure for the microstructural characterization of materials, both in mass samples (scanning electron microscopy) and in thin samples (transmission electron microscopy and microanalysis).

Services: 

Scanning Electron MicroscopyThe images obtained by scanning electron microscopy, they provide both topographic information of the surface of a rough sample (fracture facies, coatings, micro-threads etc.) and qualitative information on compositional differences, or crystal orientation of a sample polished. The R-X emission spectra of the sample, which can be purchased both with the EDX detector as WDX detectors give both qualitative and quantitative information on the composition of a sample point, a line or a small surface the same. Thus it is possible, on the one hand to determine the chemical formula of each of the phases present in the sample and observing the segregation of elements, provided that these do not occur in a submicron scale. Furthermore, the diffraction patterns of Kikuchi bands obtained with EBSD detector, can recognize crystal structures and thereafter determine both the misorientation between adjacent crystals, such as obtaining microtextures produced during the treatment of the sample under study etc. You can also simultaneously, looking forward to obtain compositional and crystalline information simultaneously over multiphasic samples, obtainEDX maps and EBSD maps . Transmission Electron MicroscopyElectron microscopy of transmission, provides information both in image as in diffraction of the same point of the sample and this information can be acquired for different inclinations of the sample, relative to the electron beam. This property gives it great versatility, as it can be characterized with both crystalline defects (dislocations, grain boundaries) and compositional (antiphase boundaries, precipitates, segregations etc.) and the crystal structure. Being able to make convergent beam diffraction (CBED),is able to determine the crystal cell, the point group and space group of crystals, micro and nano imbued , or not, in a larger sample size. Moreover, EDX spectra (obtained by the photon emission of RX) and EELS spectra (obtained as a result of the loss of energy of electrons passing through the sample), which can be acquired on different points of the sample, allow to determine chemical formulas of the phases under consideration, that can be nano-sized. Furthermore, when the transmitted beam sweeps the sample it can be obtained distribution maps of elements that can give compositional information, even at the level of an atomic column if this is sufficiently separated from its adjacent (in our team Titan Cubed distance, between atomic columns must be greater than 0.135nm). The images are acquired in high resolution due to the interference of different diffracted beams and the transmitted beam and give information about the atoms that constitute the unit cell, as long as the sample is thin enough (two or three dozen nm) and the results of the series of focus, obtained experimentally, with simulated images are compared. 0.07nm resolution allows to determine a number of crystalline structures provided as, again, the samples are adequate. The resolution of 0.135nm STEM with HAADF detector mode, allows to see compositional differences in different atomic columns, again if the samples have adequate preparation and guidance, if not the case compositional differences between nanometric phases will only be observed. FIBThe FIB which is provided, is a computer that contains two columns one for electrons and one for  ion forming a known angle. It allows to prepare samples of a wide variety of materials (metals, ceramics, semiconductors) for observation in a transmission electron microscope, being these lamellae, of substantially parallel faces, and thicknesses which  can be controlled. The sample size is typically about 20mm long by about 5 mm of width and thickness depends on the type of information required and the density of that sample.

Equipment

Scanning electron microscope

- Secondary electron detector.
- Retroscattered electron detector.
- Microanalysis via R-X (EDX) Pentafet photon energy made by Oxford (with 133eV resolution and beryllium window).
- Microanalysis via R-X (WDX) photon wavelength with two spectrometers with two crystals each (JEOL).
- The entire unit can be used in completely automated mode (including slide), controlled by the Lemas system and Link exlll.
- Special slide to be able to work the same as with a microprobe (with illumination by transparency of the lens), with thin laminates.

Transmission electron microscope

Philips CM200 transmission electron microscope with a supertwin lens, LaB6 filament, specific 0.235nm resolution and 0.144nm line; ±40º tilt, equipped with:
- EDX microanalysis (with super-ultra-thin window for light elements and 137.4eV resolution, made by EDAX with DX-4 control system).
- TV Gatan 696 camera.
- Philips PW6595/05 double-tilt sample holder.
- Philips PW6594 rotation-tilt sample holder.
- Single-tilt sample holder (PW6596) and beryllium single-tilt for microanalysis (PW6597/05).