Comparing the Efficacy of Select Natural and Synthetic Corrosion Inhibitors on Copper and Iron

Six corrosion inhibitors were evaluated for their effectiveness at preventing corrosion on copper and mild steel in a short-term experiment lasting two weeks. Half of the inhibitors tested were alcohol extracts of natural products (ginger, garlic, and black pepper), and the others were standard chemical reagents including benzotriazole (BTA), cysteine, and 5-amino-1,3,4-thiadiazole-2-thiol (AMT). Metal coupons of both mild steel and copper were immersed in a 0.007M dilute HCl solution with one of the six inhibitors or a combination of two inhibitors. The pH of each solution was monitored to track the corrosion rate and this method proved to be remarkably sensitive and nuanced, allowing for the subtleties of the decay mechanisms to be determined.