The fireside corrosion of a martensitic P92 steel with mixed sulfate deposit (Na2SO4/K2SO4 = 8:5, by weight) in the air at 650 °C was studied via X-ray diffraction, scanning electron microscope and electron probe microanalyzer and X-ray photoelectron spectroscopy. The results showed that P92 was highly susceptiblr to fireside corrosion attack. There were three corrosion layers: the Fe2O3 oxides in the outermost layer, the spinel oxides in the middle layer, and the mixed bands with oxide-sulfide between the inner oxide and the substrate. Sulfide particles were also distributed at the interface of martensitic lath in the matrix. There were different corrosion mechanisms in different corrosion layers. On the surface, basic fluxing of the oxide film destroyed the protective performance of the oxide film. At the forefront of the corrosion layer, the existence of sulfide and oxide mixed band and sulfide particles accelerated the mass transfer process and promoted the rapid oxidation of sulfide, making the oxidation rapidly penetrate the matrix. In nodular oxide, the formation of low melting point complex sulfate accelerated the mass transfer and oxidation process.

中文翻译：

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具有混合硫酸盐沉积物的 P92 钢在 650 °C 下的炉侧腐蚀

通过 X 射线衍射、扫描电子显微镜和电子探针显微分析仪和 X 射线研究了在 650 °C 空气中混合硫酸盐沉积物（Na2SO4/K2SO4 = 8:5，按重量计）的马氏体 P92 钢的炉侧腐蚀。光电子能谱。结果表明，P92 对炉侧腐蚀攻击高度敏感。腐蚀层分为三层：最外层为 Fe2O3 氧化物，中层为尖晶石氧化物，内层氧化物与基体之间为氧化-硫化物混合带。硫化物颗粒也分布在基体中马氏体板条的界面处。不同腐蚀层有不同的腐蚀机理。从表面上看，氧化膜的碱性熔剂破坏了氧化膜的保护性能。在腐蚀层的最前沿，硫化物和氧化物混合带和硫化物颗粒的存在加速了传质过程，促进了硫化物的快速氧化，使氧化迅速渗透到基体中。在球状氧化物中，低熔点复合硫酸盐的形成加速了传质和氧化过程。