Natural Products for Mild Steel Protection Corrosion Inhibition by Caryota urens and Averrhoa carambola Leaves Extract in Acid Media Testing of Caryota urens Leaves Extract in Electroplating Industries

Abstract

Access to metals has started the revolution in civilization which ultimately led to the growth of newlineindustrialization. Corrosion control of metals has technical, economical and environmental newlineimportance. The intent of this research involves the establishment of the use of green inhibitors as one newlineof the best options to protect metals and alloys against corrosion. Present work involves the newlineinvestigation on corrosion inhibition of mild steel using Caryota urens leaves extract (CUL) and newlineAverrhoa carambola leaves extract (ACL) in hydrochloric acid, sulphuric acid and citric acid media. newlineThe impact of selected plant extracts on corrosion inhibition at various acid concentrations and at newlinedifferent immersion periods was studied using weight loss technique and electrochemical methods. newlineThe performance of the selected plant extracts in organic acid viz. 1 M Citric acid by weight loss newlinemethod offered 91 % inhibition efficiency with 1.5 %v/v CUL for 48 hour immersion period which is newlinecomparable to 1 M HCl and 0.5 M H2SO4 at the same condition. Surface studies were performed by newlineusing SEM and EDX to analyze the surface morphology. To prove the probable mode of corrosion newlineinhibition mechanism, FTIR technique was employed. SEM analysis substantiates the inhibiting effect newlineof the CUL and ACL extracts showing the formation of a thin film covering and protecting the newlinereaction sites on the mild steel surface. The EDX results which show a decrease in the percentage of newlineiron and oxygen content in the presence of extracts indicating the decrease in corrosion rate. FTIR newlineanalysis showed the presence of active polar functional groups and hetero atoms with lone pair of newlineelectrons in the CUL and ACL extract. Adsorption, activation, and statistical studies were addressed in newlinethis work. Adsorption studies showed that inhibitor adsorbed on metal surface according to Langmuir newlineisotherm. The calculated values of activation energy for the CUL and ACL extract were less than 80 newlinekJ/Mole, which strongly support the physisorption of the corrosion inhibition process.