Development of an environmentally friendly protective coating for the depleted uranium–0.75 wt% titanium alloy: Part III: Surface analysis of the coating

By Roeper, Donald F.; Chidambaram, Devicharan; Clayton, Clive R.; Halada, Gary P. & Demaree, J. Derek
Published in Electrochimica Acta NULL 2006

Abstract

Molybdenum oxide-based conversion coatings have been formed on the surface of the depleted uranium–0.75 wt% titanium alloy using either concentrated nitric acid or fluorides for surface activation prior to coating formation. The acid-activated surface forms a coating that offers corrosion protection after a period of aging, when uranium species have migrated to the surface. X-ray photoelectron spectroscopy (XPS) revealed that the protective coating is primarily a polymolybdate bound to a uranyl ion. Rutherford backscattering spectroscopy (RBS) on the acid-activated coatings also shows uranium dioxide migrating to the surface. The fluoride-activated surface does not form a protective coating and there are no uranium species on the surface as indicated by XPS. The coating on the fluoride-activated samples has been found to contain a mixture of molybdenum oxides of which the main component is molybdenum trioxide and a minor component of an Mo(V) oxide.

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