一种基于层层自组装的新型EPS防腐蚀复合涂层

A New EPS Anticorrosive Composite Coating Based on Layer-by-Layer Assembly

目的探索EPS复合涂层的制备方法,并对其防腐蚀效果进行验证。方法将层层自组装技术(Lb L)引入EPS复合涂层的制备中,利用纳米SiO_2、PAH聚合弱电解质与EPS之间的静电吸附作用,制备稳定、均匀的复合涂层,采用Zeta电位、平均粒径、腐蚀失重、电化学、SEM、XRD等测试涂层稳定性和防腐蚀效果。结果 Zeta电位、溶液平均粒径测试、腐蚀失重实验和电化学实验结果表明,当纳米SiO_2溶液中SiO_2质量分数为1.5%、溶剂中乙醇质量分数为30%,PAH溶液中PAH质量浓度为2 mg/m L,EPS溶液中EPS质量浓度为200 mg/L,浸涂层数n=7时,涂层防腐蚀效果最为持久、高效、稳定。与碳钢和只浸涂EPS的碳钢相比,浸涂有Lb L的碳钢15 d腐蚀期后的腐蚀产物排列最为致密、有规律,且腐蚀电流密度变化最为平稳,具有最低电流密度和最大交流阻抗。结论得出了基于Lb L的EPS复合涂层最优参数及制备方法,与碳钢和只浸涂EPS的碳钢相比,浸涂Lb L的碳钢防腐蚀效果最好。

The work aims to explore preparation method of EPS composite coating, and verify its anti-corrosion effect. Based upon electrostatic adsorption among nano-silica and poly （allylamine hydrochloride, PAH） and entrapping extracellular polymeric substances （EPS）, a stable and uniform composite coating was prepared by introducing Layer-by-Layer （LbL） self-assembly technology. Stability and anti-corrosion effect of the coating were analyzed by means of Zeta potential, average grain diameter, corrosion weight loss experiment, electrochemical testing, X-ray diffractometer （XRD） and scanning electron microscope （SEM）. Zeta potential, average grain diameter test of nano-silica solution, corrosion weight loss experiment and electrochemical experiment indicated that, the coating had the most efficient, stable and lasting anti-corrosion effect provided with mass percent of 1.5wt%, alcohol fraction of 30%, EPS solution concentration of 200 mg/L and layer number of n=7. Scan-ning electron microscope （SEM）, XRD and electrochemical impedance spectroscopy （EIS） results showed that carbon steel coated with LbL multi-layer coating had more compact and orderly corrosion products （quantities of Fe3O4） after being exposed to corrosive conditions for 15 days, lowest corrosive electric current density and maximum impedance. Optimum parameters and preparation method of LbL-based EPS composite coating are obtained. Compared with the original carbon steel and EPS coating, the anti-corrosion effect of the multi-layer EPS coating coated with LbL is the best.