金属铀氧化的显微拉曼光谱和原子力显微镜原位研究

In-Situ Studies of Uranium Oxidation by Micro-Raman Spectroscopy and Atomic Force Microscopy

摘要:

通过光学金相、拉曼光谱和原子力显微镜分析，原位研究金属铀在大气环境、干燥空气和饱和水汽下，20~400 ℃的温度范围内样品显微形貌和氧化产物的变化情况，鉴定夹杂物、不同微区的腐蚀产物。铀在大气环境条件下吸附O2、H2O和CO2反应生成二氧化铀、铀酰化合物和碳酸铀等，干燥空气中加热后首先出现活性腐蚀亮斑，逐渐积累长大发生点蚀，并由UO2转变为U3O8。在饱和水汽中缓慢升温，UO2在260~280 ℃转化为U3O8。

Abstract:

The variations of the microscopic morphology and oxides of metal uranium were in-situ investigated in the range of 20~400 ℃ by optical metalloscopy (OM), Raman spectroscopy(RS) and atomic force microscopy(AFM). Experiments were performed in ambient air, dry air and saturated vapor, respectively. The corrosion products and some inclusions were identified. In ambient air, uranium adsorbed oxygen, water and carbon dioxide, and subsequently reacted with them resulting in forming uranium dioxide, uranyl compounds, uranium carbonate etc. Contrastively in dry air, reactive corroded spots appeared at the beginning of heating and cumulated gradually, and generated pitting, with a simultaneous constituent transformation from uranium dioxde to triuranium octoxide. Meanwhile, uranium dioxde was heated at a low rate in saturated vapor, resulting in a conversion to triuranium octoxide at the temperature of 260~280 ℃.