Scanning Electron Microscopy (SEM)
Characterization of insulating fibres and powders
Instrument: Philips XL-30 ESEM-EDX
Techniques: ‘wet’(low-pressure) mode imaging, EDX spectroscopy
Summary: In conventional SEM, the observation of insulating samples needs to deposit a gold or carbon coating on the sample surface to make it conductive. Direct observation of such samples without Au/carbon coating is available in the Philips XL-30 ESEM and the Nova200 NanoSEM when the instruments are operated under ‘wet’ mode. The upper micrograph shows wool fibres having alumina-type contaminating particles, both of them being electric-insulating. The Al2O3 contaminants were confirmed by EDX chemical analysis. The lower image shows sub-micron features of a refractory material powder of rare earth oxide. EDX spectroscopy showed chemical contents of the oxide mixture including O, La, Ce and Pr.