UC表层的X射线光电子能谱研究

Characterization of Uranium Monocarbide Surfaces by XPS

摘要:

采用X射线光电子能谱(XPS)分析研究了烧结UC(包括钚的碳化物)样品的表面层结构.分析结果表明,经大气氧化的UC表层由表及里大致组成为:少量UO2 x→UO2与UC的混合物及少量自由碳→UC基体.UC的U4f7/2峰和Cls峰结合能分别为378.2 eV和282 eV.定量分析表明,UC清洁表面的C/U原子比约为1:1,这与UC的化学组成一致,但此时仍能探测到少量固溶氧存在.初步探讨了UC在大气环境中的氧化机理.

Abstract:

The air-exposed surfaces of sintered UC samples at room temperature were examined by X-ray photoelectron spectroscopy (XPS). Elemental depth profiles reveal that the surface of UC consists of a top layer of small amounts of UO2+ ; this very thin layer is x followed by a layer containing uranium dioxide, uranium monocarbide and free carbon and then bulk UC. The binding energy of U4f7/2 and C1s peaks of UC is found to be 378.2 eV and 282 eV, respectively. Quantitative analysis indicates that the C/U atomic ratio of clean UC surfaces is approximately 1?1, which is consistent with stoichiometric UC, but there exists small amounts of dissolved oxygen on sputter-cleaned UC surfaces. The oxidation mechanism of UC has been also discussed.