复配转锈液中各组分对锈转化行为的影响

Effects of the components of a composite rust conversion solution on rust conversion behavior

[目的]针对锈蚀的固定钢铁结构无法进行返厂除锈涂装的现状,绿色转锈液的开发对锈蚀结构件的腐蚀防护及延寿具有重要意义。[方法]通过开路电位、电化学阻抗谱、极化曲线等测试方法研究了带锈Q235钢在质量分数为3%的酸性转锈液中的电化学行为,采用扫描电镜、能谱仪和红外光谱仪考察了不同转锈液对锈层的反应状态和转化膜的组成,根据接触角分析了有机树脂在转锈表面的润湿情况。[结果]在由质量分数均为1%的植酸、单宁酸和没食子酸组成的复配体系中,酸性较强的植酸能够快速溶解锈层,产生大量铁离子,铁离子再与植酸、单宁酸和没食子酸发生螯合,形成致密的锈转化膜。[结论]复配酸转锈液能够获得比单一酸转锈液性能更加良好的转化膜,与有机树脂能够较好地相容。

[Introduction]The development of an environmentally friendly rust converter has significant importance for the corrosion protection and lifespan extension of rusted steel structures,which cannot undergo rust removal and repainting in workshop.[Method]The electrochemical behavior of rusted Q235 steel in different rust converters comprising 3%(mass fraction)of single or mixed acids was studied by open circuit potential measurement,electrochemical impedance spectroscopy,and polarization curve measurement.The reaction status and composition of rust layers in different rust converters were analyzed by scanning electron microscopy,energy-dispersive spectroscopy,and infrared spectroscopy.The wettability of organic resin solution on the surface of rust conversion film was analyzed by using a contact angle goniometer.[Result]In the mixture of 1%phytic acid,1%tannic acid,and 1%gallic acid,the rust layer could be dissolved rapidly by phytic acid with strong acidity,and the large amount of iron ions generated was then chelated by phytic acid,tannic acid,and gallic acid,forming a compact rust conversion film.[Conclusion]The mixed acid can be used as a rust converter to form a conversion film with better performance than a single acid,and the conversion film is compatible with organic resins.