Evaluation of Aqueous Coffee Husks Extracts as a Corrosion Inhibitor of 1020 Carbon Steel in 1 mol L-1 HCl Solution

Corrosive processes in acidic medium reduce the performance and durability of metallic materials, causing problems to several industries. Corrosion inhibitors are commonly used to decrease these effects. As these inhibitors must be ecologically friendly currently, this work evaluated the anticorrosive effect of natural extracts of coffee husks (Coffea arabica L.) in the protection of carbon steel in 1 mol L-1 HCl solution. Extractions were performed using water as the extraction solvent. The polyphenols content increased with the extraction temperature, and the extracts were produced using 100 ºC. Extract concentrations of 10, 20 and 30 % v/v were analyzed as inhibitors for carbon steel in acid medium, using weight loss and electrochemical tests, as well as scanning electron microscopy. There was an increase in the inhibition efficiency as the extract concentration increased, reaching values around 97 % using 30 %v/v of extract for the weight loss tests.

酸性介质中的腐蚀作用会降低金属材料的服役性能与耐久寿命，给众多工业行业带来诸多困扰。当前工业界普遍采用缓蚀剂以缓解此类腐蚀危害。鉴于当前缓蚀剂需具备生态友好性，本研究针对阿拉伯咖啡（Coffea arabica L.）果壳天然提取物在1 mol·L⁻¹盐酸溶液中对碳钢的防护效果展开了评价。实验以纯水作为提取溶剂制备咖啡果壳提取物，结果显示提取物中的多酚含量随提取温度升高而上升，本研究最终采用100℃条件制备提取物。本研究选取体积分数为10%、20%、30%的提取物作为缓蚀剂，针对酸性介质中的碳钢开展缓蚀性能评价，测试方法包括重量损失法、电化学测试以及扫描电子显微镜（scanning electron microscopy, SEM）分析。实验结果表明，缓蚀效率随提取物浓度升高而提升，在重量损失测试中，采用30%（v/v）提取物时缓蚀效率可达约97%。