火电厂区域分布式光伏支架表面锌铝合金镀层的腐蚀行为

Corrosion behavior of hot-dip Zn-Al alloy coating on distributed photovoltaic bracket in thermal power plant

通过加速腐蚀试验模拟了空白Q235钢及热浸镀锌铝合金钢在火电厂酸性腐蚀环境中的腐蚀行为,通过扫描电镜和能谱仪对比了它们的腐蚀形貌和腐蚀产物组成。结果发现,锌铝合金镀层能够有效提高Q235钢的耐蚀性,因Zn和Al氧化腐蚀形成的双层致密膜层共同构成了保护Q235基体的两道防线。基于元胞自动机原理,通过Matlab软件模拟了Q235钢表面锌铝合金镀层的截面腐蚀形貌,并与在火电厂中服役的镀锌铝合金钢的实际情况进行对比,确定了镀锌铝合金钢的腐蚀规律。模拟计算了不同厚度镀锌层的腐蚀情况,再结合热浸镀工艺和光伏支架材料的现实情况,建议表面镀锌铝合金层的平均厚度至少为30μm,这样才能保证光伏支架的安全性和服役寿命。

The corrosion behavior of Q235 steel with and without a hot-dip Zn–Al alloy coating in acidic corrosion environment of thermal power plant was simulated by accelerated corrosion test.Their corrosion morphologies and components of corrosion product were compared based on the scanning electron microscopic observation and energy-dispersive spectroscopic analysis.It was found that the corrosion resistance of Q235 steel could be effectively improved by hot-dip coating with a Zn–Al alloy layer,due to the formation of a compact double-layered film comprising the oxides of Zn and Al offering two defense lines to protect the Q235 substrate.The corrosion morphology of Zn–Al alloy coating on Q235 steel substrate was simulated by Matlab software based on the principle of cellular automata and compared with the actual cross-sectional morphology of hot-dip Zn–Al alloy coated steel serving in a thermal power plant.The general corrosion rule of hot-dip Zn–Al alloy coating was then determined.The corrosion of hot-dip Zn–Al alloy coatings with different thicknesses were calculated by simulation.Considering the actual situation of hot-dip coating process and the materials of photovoltaic brackets,it is recommended that the average thickness of hot-dip Zn–Al alloy coating should be at least 30μm to ensure the safety and service life of photovoltaic brackets.