High resolution electron energy loss spectroscopy study of the oxidation of Nb(110) surface

NIOBIUM and its oxides are a new kind of materials applied in technical fields, such as catalysis, microelectronics, ceramics and optical glass. In order to understand the surface structure and catalytic activity, much work has been done on the oxidation of niobium. These results indicated that the oxidation process of niobium surface, the distribution and the structure of niobium oxides on the surface are all closely related to the condition of the oxidation process. Due to the high activity of niobium and the complexity of niobium oxide species, up to now there has not been a clear picture of the structure and the forming condition of the niobium oxides. HREELS is a powerful tool to investigate vibrational and structural properties of surface, but the HREELS study of the oxidation of Nb single crystal by O2 has never been reported before. In this note we investigated the oxidation of Nb（110） and the structure and adsorption properties of the oxide film using HREELS, UPS and AES.

高分辨连续光源原子吸收光谱法测定铀铌铅多金属矿中痕量银

铀铌铅多金属矿组成成分复杂,准确有效的测定其中的痕量银,有利于银的回收利用。采用HCl-HNO 3-HF-HClO 4处理铀铌铅多金属矿样品,以HCl(1+4)-2 g/L酒石酸为测定介质,以λAg=328.068 nm为分析谱线,建立了高分辨连续光源原子吸收光谱法(HR-CS-AAS)测定铀铌铅多金属矿样品中痕量银的新方法。对仪器参数进行了优化,确定采用迭代基线校正(IBC)背景校正方式,CCD检测器有效像素点选择5个;由银的平均吸收光谱图和吸光度-波长-时间三维吸收光谱图可知,银的CCD检测器分辨率为0.002 0 nm/pixel,λAg=328.068 nm在327.86~328.27 nm范围内没有受到溶液中其他共存元素的谱线干扰。在优化的实验条件下,银的吸光度与其质量浓度在0.40~1.60μg/mL范围内运用二次方程最小二乘法拟合校准曲线,相关系数为0.999 9,特征浓度为0.014 8μg/mL,方法检出限为0.001 3μg/mL。将HR-CS-AAS测定样品中银的参数与空心阴极灯原子吸收光谱法(HCL-AAS)相比,其检出限更低,特征浓度更低,标准溶液系列的吸光度更高。按照实验方法对铀铌铅多金属矿样品中的银进行测定,结果与电感耦合等离子体质谱法基本一致,相对标准偏差(RSD,n=9)为0.63%~3.3%。按实验方法在铀铌铅多金属矿样品中加入银标准溶液进行加标回收试验,回收率为97%~104%,满足国家地质矿产行业标准DZ/T 0130—2006的要求。

高分辨率ICP光谱仪在铌中杂质元素测定上的应用

本工作利用法国JY公司高分辨率ICP光谱仪(光栅刻线 4320gr/mm)测定铌中12个元素,减少了光谱干扰,改善了检出限。1mage Navigator 可以在2min内采集从160至420nm范围内的全部光谱,进行多元素快速定性和半定量分析。

高分辨率连续光源原子吸收仪测定矿石中铌、锆含量

由于传统方法在对矿石中铌、锆含量测定时存在较大的相对标准误差,为此提出高分辨率连续光源原子吸收仪测定矿石中铌、锆含量研究。首先将矿石进行风干、粉碎、消解等处理,对其进行合理制备;然后对TAS-990原子吸收分光光度计进行校正与参数设置,运用该仪器对制备后的矿石中铌、锆电解质浓度进行测量;最后根据测量数计算出矿石中铌、锆含量,以此实现高分辨率连续光源原子吸收仪测定矿石中铌、锆含量。经实验证明,此次设计方法相对标准误差低于传统方法。