Time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) was employed for an analysis of the rare earth element Ce in pure iron and steel. Secondary ion images showed that the amount of the segregation of Ce and its oxides was much less as the concentration of Ce decreased to about 11 ppm in the pure iron. In terms of depth profiling from the surface to the matrix, variation of the CeO⁺/Ce⁺ ratio in a Ce oxides sample and a pure Ce sample exhibited difference between oxidized state and metallic state. It was demonstrated that metallic Ce was presented when the ratio of CeO⁺/Ce⁺ decreased to approximately 2 and even smaller. Oxygen content with concentration of tens of ppm may influence the ratio obviously. Such ToF‐SIMS analysis was also feasible to discern the states of cerium in a Q345E steel with concentration in ppm level.

中文翻译：

---

通过ToF-SIMS分析确定钢中ppm铈的化学状态

飞行时间二次离子质谱法（ToF-SIMS）用于分析纯铁和钢中的稀土元素Ce。二次离子图像显示，随着纯铁中Ce的浓度降低至约11 ppm，Ce及其氧化物的偏析量要少得多。就从表面到基质的深度剖析而言，Ce氧化物样品和纯Ce样品中CeO ⁺ / Ce ⁺比的变化表现出氧化态与金属态之间的差异。结果表明，当CeO ⁺ / Ce ⁺减少到大约2甚至更小。浓度为数十ppm的氧气含量可能会明显影响该比例。这种ToF-SIMS分析对于鉴别浓度为ppm级的Q345E钢中的铈状态也是可行的。