Several fluorescent materials have been used under epoxy coatings on 7075 aluminum alloy surfaces. These fluorescent materials either fluoresce upon oxidation and are thus corrosivity indicators or they fluoresce with the products of corrosion and are true corrosion indicators. Recent work has involved using a pigmented epoxy paint, such as that used on aircraft, to see if fluorescence is still visible. Although the intensity is reduced, there is still visible fluorescence. This paper reports the results of the most promising fluorescent markers in each of the two types mentioned above. Photographic data are presented with changes of fluorescent activity with time. These two types of indicators have the potential to detect corrosion or corrosive conditions under paint coatings and could greatly reduce the costs of corrosion maintenance as well as
enhancing safety factors in aircraft. Keywords: aluminum alloys, coatings, corrosion detection, fluorescent materials