Scanning Electron Microscopy
The Philips XL30 scanning electron microscope (SEM) can be used to investigate surfaces of samples, most often on a micron and sub-micron scale. High-resolution images with an impressive depth of field are readily obtained.
Small samples and fine powders can be mounted on SEM stubs in the preparation laboratory prior to the session. Coating facilities and technical staff are on site to assist with all sample preparation requirements.
Imaging can be performed using the secondary electron (SE) detector, the backscattered electron (BSE) detector, and cathodoluminescence (CL) detector, and using the EDS. The SE detector is ideal for obtaining surface topography for a wide variety of samples. The BSE detector is ideal for analysing samples that have a wide range of atomic numbers. Examples include the observation of:
- multi-phase minerals
- different phases and inclusions in metal alloys
- gunshot residue
- heavy metal ions present in doped materials and biological systems
- failure analysis of metal welds.
The cathodoluminescence (CL), or light, detector is able to show regions in the sample that produce visible light when struck by electrons. This detector is invaluable for obtaining additional microstructural information from samples such as zircons, diamonds and zirconia and is ideal for mapping regions of interest prior to SHRIMP (sensitive high resolution ion microprobe) analysis.
Electron Backscatter Diffraction (EBSD) is fully integrated into the XL30 SEM, allowing crystallographic information to be obtained in the same session as imaging or X-ray analysis. The EBSD technique yields valuable clues about morphology, material properties and behaviours on a granular or inter-granular scale and is suitable for a wide variety of materials. Its particular strengths are in:
- phase identification and mapping of materials with similar chemistries (for example oxides, carbides or nitrides) with a spatial resolution of one micron
- identifying changes in crystallographic orientation around sites of deformation, corrosion, migration and recrystallisation to an accuracy of one degree of mis-orientation.
FIBSEM – due in 2008
In 2008 CMR will house a new focussed ion beam, field emission electron gun scanning electron microscope (FIBSEM) – this will be a unique facility costing in excess of $2 million. The FIBSEM will have usual array of SE and BSE detectors and also an integrated EDS/EBSD facility.
Scanning Electron Microscopy | Transmission Electron Microscopy | Optical Microscopy | Image Analysis | Small Angle X-ray Scattering | X-ray Diffraction | X-ray Analysis | Corrosion Testing
