Detection of Corrosion in aircraft aluminum alloys

This work shows the application of an aqueous solution of gadolinium nitrate as a contrast agent in samples of AA7075 aluminum alloy used in aircraft structures for neutron radiography (NR) detection of corrosion as the pitting and exfoliation, either hidden or not, by the same alloy. Besides this, inspection for detection of simulated corrosions of several dimensions inside a cylindrical block of aluminum alloy was carried out. The neutron radiographies were taken in the NR device of the external thermal column of the Argonaut reactor, Nuclear Engineering Institute, IEN/CNEN. An image detector was used, consisting of a gadolinium converter, 50 μm thick, and a double-coated Kodak Industrex M film.