Raman Microprobe Spectroscopy of Polyphase Ceramics

Abstract

One of the principal reasons that Raman spectroscopy has not been widely applied to problems in the characterization of ceramics is that until the recent advent of the Raman microprobe spectrometer it was not possible to localize the analysis volume to a dimension commensurate with the grain size typical of ceramic microstructures. This has proved to be an unfortunate limitation since many of the phases common to ceramic materials are strongly Raman active and generate quite distinct and recognizable Raman spectra. However, the ability to investigate regions with an optical probe as small as 1 μm in diameter, as can now be achieved in the Raman microprobe, finally enables the technique of Raman spectroscopy to complement existing microanalysis tools. To put the technique in perspective, it extends the capabilities of the optical microscope to include microanalysis just as x-ray microanalysis techniques (e.g., EDAX) have extended the capabilities of the scanning electron microscope and as x-ray microanalysis and electron energy loss spectroscopy have made the transmission electron microscope an analaytical instrument of exceptional power.