Surfaces of polycrystalline ferritic Fe–Cr steel with grain sizes of about 13 µm in diameter were investigated with surface sensitive techniques. Thin oxide layers, with a maximum thickness of about 100 nm, were grown by oxidation in air at temperatures up to 450°C and were subsequently characterized using time-of-flight secondary ion mass spectrometry (TOF-SIMS) and atomic force microscopy. Correlative microscopy was applied, which allows for element-specific depth profiles on selected grains with a particular crystal orientation. A strong correlation between the grain orientation and the thickness of the oxide layer was found. The sequence in the oxidation growth rate of ferritic Fe–Cr steel crystal planes is found to be {011} > {111} > {001}, which is unexpectedly opposed to known Fe-based systems. Moreover, for the first time, the Cr/Fe ratio throughout the oxide layer has been determined per grain orientation. A clear order from high to low of {001} > {111} > {011} was detected.

中文翻译：

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多晶 Fe-Cr 上薄氧化物层的深度剖面分析

晶粒尺寸约为 13 的多晶铁素体 Fe-Cr 钢表面微米用表面敏感技术研究了直径为 m 的。最大厚度约为 100 nm 的薄氧化物层通过在高达 450°C 的温度下在空气中氧化生长，随后使用飞行时间二次离子质谱 (TOF-SIMS) 和原子力显微镜对其进行表征。应用了相关显微镜，它允许在具有特定晶体取向的选定晶粒上获得特定元素的深度剖面。发现晶粒取向和氧化层厚度之间有很强的相关性。发现铁素体 Fe-Cr 钢晶面的氧化生长速率顺序为 {011} > {111} > {001}，这出乎意料地与已知的 Fe 基系统相反。此外，首次根据晶粒取向确定了整个氧化物层的 Cr/Fe 比。