Filtern
Dokumenttyp
- Zeitschriftenartikel (5)
- Vortrag (4)
- Beitrag zu einem Tagungsband (3)
- Sonstiges (1)
- Posterpräsentation (1)
Schlagworte
- EDX (4)
- High-resolution (3)
- Nanoparticles (3)
- SEM (3)
- T-SEM (3)
- EDS (2)
- (mu-)XRF (1)
- Ceramic (1)
- ED-EPMA (1)
- Electron backscatter diffraction (1)
Organisationseinheit der BAM
Eingeladener Vortrag
- nein (4)
It is a latent wish of any SEM/EDS (scanning electron microscope with an energy dispersive spectrometer) analyst to “see more” of the analyzed specimen, i.e. to improve the existing analytical figures of merit.
One key issue are the relatively poor limits of detection (not below 0.1 mass-%) provided by energy dispersive X-ray spectrometry (EDX) with the conventional electron excitation (ED-EPMA). This is a consequence of relatively low peak-to-background ratios and reduced energy resolution when compared to wavelength dispersive spectrometry (WD-EPMA). Recent technological developments make possible to equip the SEM with a wavelength dispersive spectrometer (WDS), so that
significantly better energy resolution can be attained. Also a relative new product that can be easily attached to a SEM/EDS system is a micro-focus X-ray source. Hence, it is possible to perform (micro-focus) X-ray fluorescence spectrometry (μ-XRF) and take advantage of the enhanced peak-to-background ratios (well suited for trace analysis). However, there are also some disadvantages: an increased measurement time and excitation with a high current in the 10s of nA range are usually required for WDS. μ-XRF provides more bulk information and poor limits of detection for light elements. By combining the advantages of these analytical techniques “seeing more” becomes possible.
Need for large-area EDS detectors for imaging nanoparticles in a SEM operating in transmission mode
(2014)
The combination of complementary characterization techniques such as SEM (Scanning Electron Microscopy), T-SEM (Scanning Electron Microscopy in Transmission Mode), EDX (Energy Dispersive X-ray Spectroscopy) and SAM (Scanning Auger Microscopy) has been proven to be a powerful and relatively quick characterization strategy for comprehensive morphological and chemical characterization of individual silica and titania nanoparticles. The selected real life test materials, silica and titania, are listed in the OECD guidance manual as representative examples because they are often used as commercial nanomaterials. Imaging by high resolution SEM and in the transmission mode by T-SEM allows almost simultaneous surface and in-depth inspection of the same particle using the same instrument. EDX and SAM enable the chemical characterization of bulk and surface of individual nanoparticles. The core–shell properties of silica based materials are addressed as well. Titania nominally coated by silane purchased from an industrial source has been found to be inhomogeneous in terms of chemical composition.
Within the last decade, silicon drift detectors (SDD) systems have become more and more popular in the field of energy-dispersive spectroscopy (EDS). The main characteristic of the SDDs is their extremely high pulse load capacity of up to 750,000 counts per second at good or reasonable energy resolution (<123eV Mn-Kα, <46eV C-Kα at 100.000 cps). These properties in conjunction with electron backscatter diffraction (EBSD) techniques and modern data processing make a range of innovative analysis options possible, not only high speed mapping but also hyperspectral imaging techniques.