ANTI-CORROSION POTENTIALS OF FRESH EXTRACTS OF OLD PERSEA AMERICANA VAR. AMERICANA SEED IN 0.5 M H2SO4 ON MILD STEEL

Anthony Chimezie Ehiemere ,P Emele ,Rosary Onyekachi Anyanwu ,U G Nwokeke

doi:10.7176/cmr/13-2-03

Abstract

An experiment to determine effective corrosion inhibition of fresh extracts from matured seed of Persea Americana var . Americana on mild steel in 0.5 M H 2 SO 4 conditions was carried out using gravimetric and electrochemical methods. The tests were carried out at room temperature for 24 hours, and also for higher temperature from 40 o C to 70 o C for 3 hours. The results showed that the seed extracts have appreciable corrosion inhibition potentials which decreased with increase in temperature. Inhibition efficiency showed that it increased with increase in inhibitor concentration across the same temperature, and similarly decreased with increase in temperature within the same concentration range. The experimental data fitted in with the Langmuir isotherm which is an indicator that the extract constituents were adsorbed on the steel surface. The Arrhenius equations showed a general increase implying that physisorption rather than chemisorptions is prevalent. The values of the heat of adsorption are all negative for temperatures at 40 o C, indicative of the fact that inhibition efficiency decreases with rise in temperature, a proof that the inhibition trend was physisorption. At temperatures of 70 o C, the values are mixed, some negative and some positive. This indicates that both physisorption and chemisorptions abound at higher temperatures. The result from potentiodynamic tests shows that reduction in current potential in the presence of the inhibitor at both concentrations implies that it is a mixed inhibitor. Keywords: Corrosion inhibition; Fresh; Higher temperatures; Langmuir isotherm; Matured; Persea Americana var. Americana . DOI: 10.7176/CMR/13-2-03 Publication date: June 30 th 2021

Highlights

1.1 Corrosion and Its Effects Metallic materials are exposed to the atmosphere for different reasons
The results show that fresh extracts of matured Persea Americana seed effectively inhibit corrosion on mild steel coupon in 0.5 M H2SO4 solution as corrodent, and that there is a marked difference between the solutions without the inhibitor from those with inhibitor
Inhibition efficiency increases with increase in inhibitor concentration generally

Summary

Introduction

1.1 Corrosion and Its Effects Metallic materials are exposed to the atmosphere for different reasons. Corrosion of a metal is said to be due to chemical or electrochemical reactions when it comes in contact with matters present in its environment [1, 2]. Corrosion of engineering structures and components in service has continued to be a huge source of concern to corrosion experts in the academia and industries. This is primarily due to its deleterious effect on material integrity and mechanical properties resulting in failure in severe cases [3]. Some of the most common ones include oxidation, uniform surface corrosion, pitting corrosion, galvanic corrosion, and microbial corrosion

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Results

Conclusion