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目的：研究十六烷基二甲基乙基溴化铵( CDAB)与NH4 SCN在硫酸介质中对Q235钢的缓蚀协同效应,并探讨其缓蚀机理和性能,以期为工业实际生产提供理论数据。方法运用失重法研究CDAB质量浓度与缓蚀率的关系,通过失重法、动电位极化曲线法和交流阻抗法分析CDAB与NH4 SCN复配后的缓蚀率和缓蚀机理。结果仅添加CDAB时,缓蚀率随着CDAB质量浓度增大而增大,但缓蚀性能并不显著,当质量浓度为10 mg/L时缓蚀率仅为85.07%；当CDAB与30 mg/L的NH4 SCN复配后,缓蚀率显著提高到96.73%,能有效抑制Q235钢在0.5 mol/L硫酸介质中的腐蚀。极化试验结果显示,该复配缓蚀剂是一种以控制阳极反应为主的混合型缓蚀剂,缓蚀率随CDAB质量浓度增大而增大,与交流阻抗法、失重法试验结果相一致。复配缓蚀剂在Q235钢表面的吸附服从Langmiur吸附等温模型,吸附吉布斯自由能△G0=-48.33 kJ/mol,为自发吸附。结论 CDAB与NH4 SCN在0.5 mol/L硫酸介质中具有优异缓蚀协同效应,能有效抑制腐蚀介质对Q235钢在的腐蚀,复配缓蚀剂具有较高的缓蚀率。

Objective In order to provide theoretical data for industrial production,the synergistic corrosion inhibition effect of cetyldimethylethylammonium bromide (CDAB) and NH4SCN for Q235 steel was investigated in 0. 5 mol/L sulfuric acid solution, and the corrosion inhibition mechanism and performance were explored. Methods Firstly, the relationship between the corrosion in-hibition efficiency and the concentration of CDAB was studied by the weight loss method. Then, the corrosion inhibition efficiency and mechanism of the compound inhibitor were analyzed by weight loss measurements, potentiodynamic polarization curves and electrical impedance spectroscopy ( EIS) . Results The results of weight loss method showed that CDAB had a low corrosion inhibi-tion efficiency when acted alone, and the inhibition efficiency increased with the increasing CDAB concentration. The corrosion in-hibition efficiency was only 85. 07% when the concentration of CDAB was 10 mg/L, while the inhibition efficiency increased to 96. 73% when CDAB was compounded with 30 mg/L NH4 SCN. The experimental results revealed that the corrosion of Q235 steel in 0. 5 mol/L H2 SO4 solution was strongly suppressed by the compound inhibitor. The polarization curve results showed that the compound inhibitor used in this paper was a mix-type inhibitor which mainly retarded anodic process, and the inhibition efficiency increased with the increasing CDAB concentration. The anti-corrosion performances determined by the potentiodynamic polarization curve, weight loss method and EIS were almost consistent. The adsorption of the compound inhibitor on Q235 steel surface abided the Langmiur's adsorption isotherm and the Gibbs free energy of adsorption△G0 was-48. 33 kJ/mol. The adsorption was a sponta-neous chemisorption process. Conclusion Composite of CDAB and NH4 SCN showed excellent synergistic effect in the presence of 0. 5 mol/L sulfuric acid solution,and the corrosion of Q235 steel in 0. 5 mol/L sulfuric acid solution was effectively suppressed by the compound inhibitor. The compound inhibitor had a high corrosion inhibition efficiency.