ABSTRACT

The experiments were performed to investigate the corrosion behavior of 15CrMo steel in the saline (Na₂SiO₃) water/steam. The samples was analysed using scanning electron microscopy/energy dispersive spectrum (SEM/EDS) and X-ray diffraction (XRD). The results indicate that the dissolved Na₂SiO₃ in the steam/liquid phase has obvious effects on the corrosion. In the steam phase, the main corrosion products are crystal NaFe(SiO₃) and Fe₃O₄. The stick-shaped microstructures (T = 280°C) are gradually converted to acicular-shaped microstructure (T = 320°C). The acicular structures connect with each other under higher temperature (T = 360°C). The relative contents of elemental Fe are 65.65%, 65.39% and 66.5% under the three temperatures, which present little changes. In the liquid phase, the main corrosion product in matrix phase is only NaFe(Si₂O₆) regardless of temperature. The surface is covered by scattered clusters with branches in radical pattern. The clusters accumulated gradually with temperature increasing. The relative content of elemental Fe decreases from 38.11% to 24.69%.

摘要

进行实验以研究 15CrMo 钢在盐水 (Na ₂ SiO ₃ ) 水/蒸汽中的腐蚀行为。使用扫描电子显微镜/能量色散光谱 (SEM/EDS) 和 X 射线衍射 (XRD) 分析样品。结果表明，溶解在汽/液相中的Na ₂ SiO _{3对腐蚀有明显的影响。}在蒸汽相中，主要的腐蚀产物是晶体NaFe(SiO ₃ )和Fe ₃ O ₄。棒状显微组织 ( T  = 280°C) 逐渐转变为针状显微组织 ( T = 320°C）。针状结构在较高温度（T  = 360°C）下相互连接。三个温度下元素Fe的相对含量分别为65.65%、65.39%和66.5%，变化不大。在液相中，无论温度如何，基体相中的主要腐蚀产物只有NaFe(Si ₂ O _{6 )。}表面被分散的簇覆盖，分支呈激进图案。随着温度的升高，簇逐渐聚集。元素Fe的相对含量从38.11%下降到24.69%。