耐候钢表面预处理对其腐蚀行为的影响

Influence of surface pre-treatment on corrosion behavior of weathering steel

通过向带锈耐候钢表面喷淋锈层稳定化剂进行预处理,使锈层表面形成了一层化学转化层,并进而研究了其对耐候钢继续腐蚀行为的影响。利用干湿循环交替腐蚀(CCT)、增重实验、场发射扫描电镜(SEM)及能谱仪(EDS)、X射线衍射分析仪(XRD)和电化学工作站等实验手段对经过预处理及未处理样品进行对比测试。结果表明:该转化层对腐蚀性离子Cl-有显著的拦截效应,并导致样品在腐蚀过程中增重减缓;预处理不改变腐蚀产物的类型,但会造成锈层内非晶相比例上升并使锈层颗粒更加细小;转化层的短期效应与长期影响不同,转化层的存在总体上有利于加速锈层稳定化。

By spraying the surface of rusted weathering steel with rust stabilizer to pretreat the samples,a chemical conversion layer was formed,whose influence on further corrosion behavior of the steel was studied. Wet/dry cyclic corrosion test( CCT),weight gaining measurement,scanning electron microscopy( SEM), energy dispersive spectroscopy( EDS), X-ray diffraction( XRD) and electrochemical impedance spectroscopy( EIS) had been carried out on samples with and without conversion layers. It is found that an obvious obstruction effect on Cl-can be produced by the conversion layer which results in slower weight gaining during corrosion of samples. The pre-treatment does not change types of corrosion products in the rust layers but results in higher ratio of amorphous phase and finer morphology in the rust layers. The short term effect of the conversion layer is different to its long term influence. Occurrence of the conversion layer will promote rust layers on weathering steel to stabilize in general.