节节草提取液自组装膜在盐酸中对Q235钢的缓蚀作用

Corrosion Inhibition of Self-Assembled Film of Equisetum Ramosissimum Extract for Carbon Steel in HCl Solution

节节草提取液对碳钢在盐酸中的腐蚀具有较好的抑制作用,但研究不够深入。以节节草植物提取液(简称为ERE)为成膜材料,采用浸泡方式在Q235钢表面制备了自组装膜。利用傅里叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)对膜层进行了表征,证实了ERE主要通过含氧极性基团在Q235钢表面吸附成膜。利用极化曲线和交流阻抗谱考察了ERE膜在盐酸中对Q235钢的缓蚀性能,结果表明:ERE膜是通过同时抑制Q235钢阴、阳极腐蚀反应达到缓蚀目的;同时发现ERE膜对Q235钢的保护性能主要取决于自组装的工艺条件,包括提取液浓度、浸泡时间和组装温度;在优化试验条件(ERE浓度1 000.0 mg/L,组装温度50℃,时间90 min)下获得的ERE膜对Q235钢具有较好的保护效果,此结果被扫描电镜(SEM)和激光共聚焦显微镜(CLSM)分析验证。采用Langmuir、Temkin和Dhar-Flory-Huggins模型拟合提取液中的有机分子在碳钢表面的吸附行为,结果表明ERE膜中的有机分子之间存在相互作用力,且组装过程中平均每个有机分子的吸附导致3个以上水分子的脱附。

A self- assembled film was fabricated on the Q235 steel surface with the plant extract of equisetum ramosissimum （ERE） by a simple immersion method. The prepared film was characterized by Fourier transform infrared （FTIR） spectroscopy and X - ray photoelectron spectroscopy （XPS）. The surface analysis revealed that the organic molecules were adsorbed on Q235 steel surface mainly through oxygen- containing polar groups, and thereby forming a protective film. The corrosion inhibition effect of the ERE film on Q235 steel in HCI solution was investigated by polarization curve and electrochemical impedance spectroscopy. Results showed that the ERE film behaved via inhibiting both the anodic and the cathodic reactions of corrosion process. Also, the protection ability of ERE film was strongly dependent on the assembly conditions, including the plant extract concentration, immersion time and assembly temperature. The ERE film obtained from an optimized assembly system （ 1 000.0 mg/L ERE, 50℃,90 min） provided good corrosion protection for Q235 steel in HC1 solution, which was confirmed by the results of scanning electron microscopy （ SEM ） and eonfocal laser scanning microscopy （ CLSM ） measurements. The adsorption of organic molecules of plant extract on the Q235 steel surface under experimental conditions was discussed on the basis of Langmuir, Temkin and Dhar- Flory-Huggins models, and the analysis results suggested that there was mutual interaction among the organic molecules in the ERE film, and each organic molecule replaced more than three water molecules during the assembly process.