Microscopy can give useful information regarding the extent or mode of corrosion degradation or failure. The range of corrosion testing techniques is therefore supported by electron, optical and atomic force microscopy facilities.

The electron microscopy unit incorporates both transmission and scanning electron microscopes, along with associated sample preparation facilities. MERI's Environmental Scanning Electron Microscope (ESEM) allows non-conducting samples, such as paint coatings, to be examined without the need to render them conductive.

(Scanning electron microscope (SEM) image showing corrosionproducts on hot-dip galvanized steel after immersion in sodium chloride solution)

The range of optical microscopes has recently been augmented by the acquisition of an infinite focus microscope (IFM). A frequent problem with optical microscopy is that the depth of field available is not sufficient to image samples with an irregular surface topography. The IFM is able to overcome this limitation by taking a series of images between two focal limits. Computer software then reconstructs a complete image from the individual ‘slices’. In addition to imaging, parameters such as surface roughness and value of voids can also be quantified.