Electron backscatter diffraction from unpolished particulate specimens: Examples of particle identification and application to inhalable mineral particulate identification

By simply crushing mineral grains, suspending the powder in a liquid, and dispersing the suspension on a suitable substrate, it is possible to collect adequate compositional and structural information to identify an unknown phase using a scanning electron microscope (SEM) equipped with an energydispersive X-ray spectrometer (EDS) and an electron backscatter diffraction system (EBSD). This technique could have important applications in the identification of inhalable particulate material. A simple test is presented to show how SEM/EDS/EBSD data are used to accurately determine the identity of mineral particles. Individual EBSD patterns contain more useful structural information and can be collected and interpreted more quickly than individual selected-area electron diffraction patterns collected with a transmission electron microscope. A case study is presented as an example of how EBSD is able to determine the phase identity of a potentially asbestiform mineral.