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.

酸性介质中的腐蚀过程会劣化金属材料的性能并缩短其服役寿命，给众多工业领域带来诸多难题。缓蚀剂（corrosion inhibitor）是目前常用于缓解此类腐蚀危害的手段。鉴于当前缓蚀剂需具备生态友好性，本研究评估了阿拉伯咖啡（Coffea arabica L.）果壳天然提取物在1 mol·L⁻¹盐酸溶液中对碳钢的缓蚀防护效果。萃取过程以纯水作为萃取溶剂，提取物中的多酚含量随萃取温度升高而增加，本研究选用100℃条件下制备得到的提取物开展后续测试。本研究选取体积分数为10%、20%及30%的提取物作为酸性介质中碳钢的缓蚀剂，采用失重法、电化学测试以及扫描电子显微镜（scanning electron microscopy）对其缓蚀性能进行表征。实验结果表明，缓蚀效率随提取物浓度升高而提升，在失重法测试中，当提取物体积分数为30%时，缓蚀效率可达约97%。