Investigation was
conducted on the application of plant extracts as a protection technique
against corrosion-based failures of mild steel in an acid medium. In the past,
attention was focused on the application of toxic and environmentally
unfriendly inhibitors to check the menace of corrosion. In this article,
however, attention was diverted to the application of eco-friendly organic
inhibitors to quench the corrosion of mild steel and its alloys in acid media.
To accomplish this, inhibitors of plants origin such as red onion skin and palm
kernels were procured and their chemical compositions analyzed and assessed for
their suitability in corrosion inhibition. Laboratory experiments involving 5 cm
x 2 cm x 0.05 cm steel coupons in a solution containing 1M, 2M, 3M and 4M
concentrations of the hydrochloric acid and the plant extracts were conducted
at different temperatures and exposure times. Various inhibition efficiencies
were obtained for the two plant extracts based on variations in acid medium
concentrations, inhibitor’s concentrations and exposure times. The results
obtained show that red onion extract was able to give a better inhibition
efficiency than the palm kernel oil extract in all respects on the average of
the five tests conducted. This study has revealed the fact that extracts of
plant origin has capacity to protect engineering materials such as mild steel
against corrosion. Chemical compositions of red onion extract however, makes it
a better corrosion inhibitor than the palm kernel extract.
