Study on interface of Al/depleted uranium and Au/depleted uranium layers deposited by magnetron sputtering

Abstract

Aluminum/depleted uranium/aluminum (Al/DU/Al) and gold/depleted uranium/gold (Au/DU/Au) "sandwich structure" films are deposited by magnetron sputtering. Diffusions of Al/DU and Au/DU interface of these samples are investigated by high resolution scanning electronic microscope, X-ray diffraction, X-ray photoelectron spectrometer and scanning auger microprobe. The results show that deposited DU layer is of columnar grain. Significant diffusion takes place at Al/DU interface. Intermetallic compounds of Al2U and Al3U are formed at Al/DU interface by chemical reaction between Al and DU which induces chemical shift toward high binding energy of Al 2p and toward low binding energy of U 4f. Microdosages of O exist in Al over-layers as Al2O3, in Al/DU interface as Al2O3 and oxidation of uranium, and in DU layers as oxidation of uranium respectively. Just simple physical diffusion takes place at Au/DU interface. Binding energies of Au 4f and U 4f shift toward high-energy tail induced by cluster effect at the Au/DU interface. Microdosages of O exist at Au/DU interface and in DU layers as oxidation of uranium. Diffusion at the Al/DU interface is more obvious than at Au/DU surface. Under the condition of the same thickness valuses Al over-layer is more effective than Au over layer to protect uranium layer from oxidging.