Interface structure and corrosion resistance of Ti/Cr nanomultilayer film prepared by magnetron sputtering on depleted uranium.

Uranium has broadened utility in military and civilization; however, it is extremely apt to oxidation corrosion. Ti/Cr nanomultilayer film was prepared by unbalanced magnetron sputtering on the surface of depleted uranium (DU) to improve its corrosion resistance. The SEM morphologies show that Ti/Cr multilayer film has fine grain and high density. The Auger electron spectroscopy is used to investigate the depth profiles of Ti, U, and O elements of interface between DU substrate and the Ti interlayer, and indicates that the mutual diffusion area of U and Ti is formed at the interface. The TEM cross-section microstructure shows that the multilayer film has alternative Ti and Cr layers and form a perfect modulation structure. The modulation period is measured to be 4.8 nm in TEM morphology, the thickness ratio of Ti to Cr could be estimated to be about 1:2. Potentiodynamic polarization curves show that, after depositing Ti/Cr nanomultilayer film, the corrosion potential increases while the corrosion current density decreases obviously. The surface of Ti/Cr nanomultilayer film exhibits a pseudo passivation behavior when the polarization potential increased from -50 to 400 mV. It was indicated that, after depositing Ti/Cr nanomultilayer film by unbalanced magnetron sputtering, the corrosion resistance of DU was effectively improved.