ABSTRACT In this work, the plant alkaloid Voacangine, isolated from the bark of Tabernaemontana contorta, was examined as a corrosion inhibitor for steel in 1 M hydrochloric acid. The study was carried out using a comparative approach where several independent methods (spectroscopic solution analysis, electrochemical impedance, potentiodynamic polarisation and mass loss measurements) were performed in order to strengthen the validity of the results. All the findings revealed to be in close agreement with each other. Voacangine was determined to be a mixed corrosion inhibitor and to closely follow Langmuir-type adsorption onto active corrosion sites on the metal surface. The maximal inhibition efficiency was 90% which is lower than other comparable species. This deficiency was ascribed to the presence of a basic nitrogen group causing a degree of steric hindrance for the adsorption.

中文翻译：

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溶液分析、电化学和质量变化对植物生物碱 Voacangine 对碳钢的抑制作用的比较研究

摘要 在这项工作中，从 Tabernaemontana contorta 的树皮中分离出的植物生物碱 Voacangine 在 1 M 盐酸中被用作钢的腐蚀抑制剂。该研究使用比较方法进行，其中进行了几种独立的方法（光谱溶液分析、电化学阻抗、动电位极化和质量损失测量）以加强结果的有效性。所有的发现都表明彼此非常一致。Voacangine 被确定为一种混合腐蚀抑制剂，并且在金属表面上的活性腐蚀位点上密切遵循 Langmuir 型吸附。最大抑制效率为 90%，低于其他同类物种。