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对常用的Inconel 690合金进行模拟压水堆(PWR)一回路条件下的堆外高温动水回路加Zn腐蚀实验,加锌浓度为0和50μg/kg的堆外高温动水回路腐蚀实验。实验1200 h后,对690合金表面氧化膜进行SEM表面形貌观察,EDS元素面扫描分析,XPS元素深度分布分析和小角X射线衍射(GIXRD)分析。结果表明,未加锌的样品,氧化膜颗粒粗大、疏松,加锌样品表面形成的氧化膜颗粒细小,与基体结合紧密,氧化膜晶粒尺寸服从Gauss函数分布规律。加锌实验后,氧化膜厚度明显减薄。同时,Zn主要分布在氧化层内部,最高值出现在外层氧化膜靠近表面处。加锌后,在氧化膜中形成了Zn Cr2O4和Zn Fe2O4化合物,热力学稳定性更高,更具有保护性。
The common Inconel 690 alloy was subjected to the corrosion test of Zn added to the hydrothermal loop outside the reactor in the first stage of the PWR and the corrosion test of the hydrothermal loop at the heap temperature of 0 and 50 μg / kg. After 1200 h of experiment, the surface morphology of the 690 alloy oxide film was observed by SEM, EDS elemental surface scanning analysis, XPS element depth distribution analysis and small angle X-ray diffraction (GIXRD) analysis. The results show that the oxide film is coarse and loose with no zinc addition. The oxide film formed on the surface of the zinc-added sample is small and tightly bonded with the matrix. The grain size of the oxide film follows Gauss function distribution. After adding zinc test, the thickness of oxide film is obviously thinned. At the same time, Zn is mainly distributed in the oxide layer, the highest value appears in the outer oxide film near the surface. After zinc is added, Zn Cr2O4 and Zn Fe2O4 compounds are formed in the oxide film, which have higher thermodynamic stability and more protection.