3-D tomography by automated in situ block face ultramicrotome imaging using an FEG-SEM to study complex corrosion protective paint coatings

Aircraft coatings are generally multi-layered with both barrier properties and are corrosion inhibitor filled to prevent corrosion. A new technique, automated in situ block face ultramicrotome imaging using an FEG-SEM has been employed for high resolution 3-D imaging of such aircraft coatings. A pristine and a cracked aged coating were visualised by this method clearly showing the coatings microstructure and subsequent crack growth properties. Filler particles were segmented and labelled allowing the coating to be more clearly visualised and enabling statistical particle analysis and meshing. Finally the method was used to investigate the inhibitor leaching properties of four aircraft primers.