The Inhibitive Action of Castor Seed Oil Toward the Corrosion of Aluminum in Saline Medium

Corrosion of metal is a costly material science problem which originates from the day of metal discovery. Corrosion inhibitor usage is an effective way of addressing metallic corrosion in aggressive environments but continued usage of synthetic chemicals for inhibiting corrosion is indefensible as a result of toxicity of the chemicals to the environmental ecosystem. Eco-friendly corrosion inhibiting alternatives are therefore needed. In view of this, castor seed oil was evaluated as anti-corrosion protection of aluminum surfaces in saline medium using weight loss and potentiodynamic polarization methods at 304 K. The obtained results show that castor seed oil on aluminum in saline medium decreased the corrosion rate at different concentrations studied. Inhibitor efficiency (IE) of 85.19% at 0.5 g/L and 41.16% at 0.1 g/L castor seed oil was obtained after 48 h of immersion, respectively, which indicates the inhibition efficiency of the inhibitor increased with an increase in concentration of inhibitor at the studied temperature. The presence of castor seed oil as corrosion inhibitor shows increased inhibition efficiency, potential value and polarization resistance with decreased current density. The inhibitor is a mixed-type inhibitor that can control both cathodic and anodic corrosion which obeyed Langmuir adsorption isotherms. © 2018, ASM International.