输电杆塔材料在海洋大气环境中的初期腐蚀行为

Initial Corrosion Behavior of Transmission Tower Materials in Ocean Atmosphere

研究了南方电网杆塔材料Q235、Q345以及镀锌钢在海洋大气环境中的初期腐蚀行为。利用SEM、EDS分析了试样表面锈层的微观形貌和化学成分,利用X射线衍射仪分析了锈层的物相组成,并用失重法计算了腐蚀速率。结果表明,除了Q345的腐蚀速率略低于Q235外,这两种钢材的初期腐蚀行为非常接近,腐蚀产物主要为γ-Fe OOH和α-FeOOH,这种腐蚀产物疏松多孔,存在大量裂纹。海洋环境中氯离子的存在促进了腐蚀产物的形成,从而加速了基体的腐蚀;镀锌钢表层为相对致密的氧化锌,没有铁的氧化物,因此其腐蚀速率很低,表现出了良好的耐腐蚀性。

The initial corrosion behaviour of China southern power grid transmission tower materials including Q235, Q345 and galvanized steel in the ocean atmosphere were investigated. SEM and EDS were applied to study the morphology and chemical compositions of the rusty scale on samples surface. X-ray diffraction （XRD） was used to analyze the phase constitution of rust scale. The corrosion rate was calculated by mass loss method. The results show that the initial corrosion behavior of Q235 and Q345 is relatively close except that the corrosion rate of Q345 is slightly lower than that of Q235. The corrosion products mainly consists of γ-FeOOH and α-FeOOH. The corrosion products are loose and porous, and furthermore many cracks are observed in them. The existence of chloride ion in ocean atmosphere can promote the formation of corrosion product. The rust layer on galvanized steel surface only includes zinc oxide which is relative compact, but without Fe oxide. So the corrosion rate of galvanized steel surface is the lowest, which can exhibit better corrosion resistance.