材料期刊网

用XPS分析不同离子选择性涂层下碳钢表层的化学组成.结 果表明，SO2-4型阴离子选择性和Na+型阳离子选择性涂层下碳钢表面锈层的主要 成分是含结合水的Fe(OH)2和少量FeO，SO2-4型阴离子选择性/Na+型阳离子选 择性双极涂层下碳钢表面的主要成分是Fe0,Fe2+所占比例很少.在涂装阴离子选择 性涂层的碳钢表面可以检测到比较明显的Cl-的XPS信号，而在涂装阳离子选择性涂层和双 极性涂层的碳钢表面则不明显.

Ion-selective (anion-selective,cation-selective and bipolar) phenolic coatings were prepared by mixing phenolic varnish with ion ex changers.SO2-4-type anion exchanger resin and Na+-type cation exchange r resin were utilized as anion and cation exchangers respectively.The bipolar co ating consisted of an anion-selective inner layer and a cation-selective outer l ayer.The corrosion compositions of carbon steel depriving of the painted ion-sel ective coatings after exposure in 3%NaCl solution for 30 days were investigated by XPS.The research results of XPS showed that the main compositions in the surf ace layer of carbon steel are Fe2+,OH-,O2- and Cl-under SO2- 4-type anion-selective coating,whereas the main compositions are Fe2+, Fe0,OH-,and O2- under Na+-type cation-selective and SO2-4-ty pe anion-selective / Na+-type cation-selective bipolar coatings.The XPS signal o f Cl-can be inspected obviously on the surface layer of carbon steel with anio n-selective coating,whereas there is no obvious signal in the case of cation-sel ective and bipolar coatings.This indicated that Cl- could migrate from the NaC l solution to the substrate metal when carbon steel covered with anion-selective coating,whereas the migration of Cl- would be blocked in the case of cation-se l ective and bipolar coatings.From these results,it can be concluded that SO2- 4-type anion-selective coating has poor corrosion resistance,Na+-type cati on-selective coating has better corrosion resistance,and SO2-4-type anio n-selective/Na+-type cation-selective bipolar coating has excellent corrosion resistance.