'Aluminised' Inconel is made commercially by undisclosed methods. Consequently its microstructure is being characterised. This has been done using : optical microscopy, electron microprobe analysis, Auger microprobe analysis, X-ray diffraction, Auger mapping, Digimapping, and multiple quantitative electron microprobe point analyses. The results obtained are combined to show how it has been possible to characterise 'the structure' of such a coating.