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利用扫描电镜、电子探针和X射线衍射技术对某电厂高温高压水蒸汽工况下运行15万h的10CrMo910钢主蒸汽管形成的氧化膜进行形貌、结构、成分及物相分析,结果表明:氧化膜外表面形貌呈丘状或蘑菇云状,低倍下横断面呈石状,有明显分层,层间存在大量孔隙;内层氧化膜结构致密,外层氧化膜结构疏松,但无贯穿内、外氧化层的缝隙或孔洞链;氧化膜晶粒大多为纳米晶粒,少量为微米晶粒,部分晶粒之间存在较大尺寸的片状晶粒;在氧化膜横断面上,O、Fe的分布较为均匀;外层氧化膜中的Cr、Mo含量较低,且分布均匀;内层氧化膜中的Cr、Mo含量显著高于外层氧化膜,较外层氧化膜有一突变,且Cr、Mo分布存在浓度梯度,在靠近内层-外层氧化膜结合处,内层Cr、Mo含量最高,然后依次降低;Cr、Mo的分布特征与氧化膜的形成、元素扩散及其挥发有关;氧化膜产物为Fe3O4和FeCr2O4.
The morphology, structure, composition and phase analysis of the oxide film formed on the main steam tube of 10CrMo910 steel, which was operated at high temperature and high pressure steam in a power plant for 150,000 h, were analyzed by means of scanning electron microscopy, electron probe and X-ray diffraction. : The morphology of the outer surface of the oxide film is mound or cloud of mushrooms. The cross section of the oxide film is stone-shaped at low magnification, with obvious delamination and a large number of pores between layers. The inner oxide film is compact in structure and the outer oxide film has a loose structure, Which penetrates through the gaps and holes in the inner and outer oxide layers. Most of the oxide film grains are nanocrystalline grains, a small amount of them are micron grains and some larger-sized sheet-like grains exist between some of the grains. In the cross section of the oxide film, O and Fe are relatively uniform. The content of Cr and Mo in the outer oxide film is relatively low and evenly distributed. The content of Cr and Mo in the inner oxide film is significantly higher than that of the outer oxide film, which is higher than that of the outer oxide film , And there is a concentration gradient in the distribution of Cr and Mo. In the vicinity of the inner-outer oxide film, the Cr and Mo contents in the inner layer are the highest and then decrease in sequence; the distribution characteristics of Cr and Mo are related to the formation of oxide film, Volatile; oxide film products for Fe3O4 and FeCr2O4.