Q235钢在西沙大气环境中的初期腐蚀行为

在西沙群岛典型的高温、高湿和高盐分大气环境下对Q235钢进行了 1个月短期暴晒实验，利用扫描电镜、电子探针、激光拉曼和X射线衍射仪等观察分析了暴晒后样品的表面形貌、腐蚀产物成分和锈层元素分布。结果表明：Q235钢形成的锈层疏松多孔，多裂纹，对基体没有保护作用。由于Cl^-的侵蚀作用，锈层和基体之间发生氧化还原反应，加速了基体的腐蚀。碳钢在西沙暴晒1个月后外表层的腐蚀产物主要有：Fe₈(O,OH)₁₆Cl_1.3，Υ-FeOOH， β-FeOOH及少量α-FeOOH等，锈层内部不同位置的产物基本相同，主要为Fe₃O₄，Υ-Fe₂O₃以及少量的Υ-FeOOH、β-FeOOH等。

CORROSION BEHAVIORS AT THE INITIAL STAGE OF Q235 STEEL IN XISHA ATMOSPHERE

The rust layer formed on the surface of Q235 steel subjected to a high temperature and high humidity marine atmosphere in Xisha Islands was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), electron probe micro analyzer (EPMA) and Raman Spectrum (RS). The results showed that corrosion behavior of Q235 steel was more severe in Xisha atmosphere than in other marine environments. The surface morphology was observed by SEM and the distributions of elements were analyzed by EPMA. There were many cracks and holes in the rust layer. Cl^- can penetrate into the rust-metal interface along the cracks and holes in the Q235 steel rust film. Outer rust of Q235 steel was mainly composed ofβ-FeOOH,Υ-FeOOH and a littleα-FeOOH. Much iron oxide, such as Fe₃O₄,Υ-Fe₂O₃ were found in the inner of rust layer. These iron oxides could be deoxidized from FeOOH, and this can accelerate oxidation of substrate steel.