Micro-Raman spectroscopy is a powerful tool that has wide application in the field of materials characterization. Micro-Raman spectroscopy can be easily employed to characterize thermal stresses in layered ceramics, distribution of residual and applied stresses in ferroelastic ceramics, molecular structure of supported metal oxides, or absorption of different species on the catalytically active surfaces. It is also well suited to study the molecular form of the absorbed oxygen or other ions or free radicals which is especially important for the understanding of the structure and dynamics of the solid surfaces during exposure to different gaseous media. The non destructive nature of Raman spectroscopy, ease of sample handling, the 1 micro m laser spot size, the ability to perform confocal measurements give an unprecedented possibilities for materials characterization especially if combined with ac impedance characterization of ceramics for energy application.
The proposed micro-Raman spectrometer coupled with Medusa test stand is equipped with three different lasers, which are computer selectable, it is directly coupled to the optical microscope, it provides a spectral resolution of ~1 cm-1 and the spectral range limited only by the CCD sensitivity (~1 micro m, in red), the continuous scanning mode allows Raman spectra to be scanned across and read from the 2-dimensional CCD detectors in multiples of pixels and sub-division of pixels to enhance spectral band shape. The instrument allows performing the confocal measurements made independently of the spectral resolution. The micro-Raman spectrometer is equipped with XYZ mapping stage which allows using it as Raman microscope. An automated mapping stage provides a step resolution of 0.1 microns. The automated z-control (autofocus) provides a step resolution of 0.5 microns. The use of CCD detectors with a Raman microscope provides capabilities for direct 2-D Raman imaging experiments. The Raman spectrometer is equipped with two external hot stages both for in-situ heating experiments and for use them as catalytic reactor system. One stage cover the range of temperatures from the liquid nitrogen to 600 deg C, and a second stage is used for heating experiments from room temperature to 1500 deg C. They both can be used for heating (sometimes cooling) experiments to study the SOFC and oxygen separation membranes behavior. In addition to hot stages, the micro-Raman spectrometer is be coupled to 850C Scribner Test Stand and ProboStat cell system which allows simultaneous electrochemical characterization of SOFC, oxygen separation membrane, or sensor performance and in-situ characterization of catalytic activities of the materials for energy application.
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