Abstract
U-6Nb is a uranium alloy containing 6 wt% niobium that possesses high corrosion resistance. The structure and composition of the passivating oxide layer formed on air-aged U-6Nb, which gives the material its corrosion resistant properties, was characterized using surface scattering techniques. Stable oxide layers formed on the surface of a set of U-6Nb alloy thin films under ambient conditions were investigated using neutron reflectometry (NR), x-ray reflectometry (XRR) and grazing incidence x-ray diffraction (GIXD). The passivating oxide was composed of approximately 27% U, 5% Nb, and 68% O, primarily consisting of a thin niobium oxide layer (5.5 ± 0.4 nm) separating a thicker UO2 layer (27.1 ± 2.3 nm) from the underlying U-6Nb alloy. A critical density of enriched niobium oxide at the metal-oxide interface is hypothesized to limit oxygen diffusion and confer high corrosion resistance to the alloy.
| Original language | English |
|---|---|
| Article number | 152356 |
| Journal | Journal of Nuclear Materials |
| Volume | 539 |
| DOIs | |
| State | Published - Oct 2020 |
| Externally published | Yes |
Funding
This work was supported by the US Department of Energy through the Los Alamos National Laboratory . Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract No. 89233218CNA000001 ) and by the Independent Research and Development program from the National Science Foundation (J. M.). The content is solely the responsibility of the authors and does not necessarily represent the official view of the National Science Foundation. This work benefited from the use of the time-of-flight neutron reflectometer (Asterix) at the Lujan Neutron Scattering Center at LANSCE. This work was supported by the US Department of Energy through the Los Alamos National Laboratory. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract No. 89233218CNA000001) and by the Independent Research and Development program from the National Science Foundation (J. M.). The content is solely the responsibility of the authors and does not necessarily represent the official view of the National Science Foundation. This work benefited from the use of the time-of-flight neutron reflectometer (Asterix) at the Lujan Neutron Scattering Center at LANSCE.
Keywords
- Corrosion
- Neutron reflectometry
- Sputtered films
- Uranium-niobium alloys
- X-ray diffraction