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本文通过对锅炉水冷壁管向火面外壁腐蚀产物的 x 射线衍射和扫描电镜(SET)的分析,阐述了水冷壁管向火面外壁腐蚀产物为双层结构。其外层灰白色物相为 FeS,内层灰黑色物相为 Fe_(1-x)S 和 Fe_3O_4。综合试验分析结果认为:由于水冷壁管表面有碱式硫酸盐化合物的存在,当环境为缺氧气氛时,能产生游离态的活性硫,硫与铁反应生成 FeS。FeS 与 Fe 形成共晶物,这种共晶物与氧气又反应生成 FeO和 FeS,这样一个交替反应过程的继续,使得水冷壁钢管发生氧化和硫化腐蚀。
In this paper, by analyzing the X-ray diffraction and scanning electron microscopy (SEM) of the corrosion products of boiler water wall to the outer wall of the fire surface, the corrosion products of the outer wall of the water wall to the fire surface are described as double-layer structure. The outer gray phase is FeS and the inner gray black phase is Fe_ (1-x) S and Fe_3O_4. The results of the comprehensive test show that due to the presence of basic sulfate compounds on the surface of the water-cooled wall tube, free sulfur can be generated when the environment is oxygen-deficient, and sulfur reacts with iron to form FeS. FeS and Fe form a eutectic, this eutectic reacts with oxygen to form FeO and FeS, so that an alternating reaction process continues, making the water wall steel pipe oxidation and sulfide corrosion.