Inhibitive Effect by Ricinus communis on the HCl/H3PO4 Acid Corrosion of Aluminium Alloy

• Published in: International journal of electrochemical science 2012-12, Vol.7 (12), p.11706-11717
• Main Authors: Abdulwahab, M., Popoola, A.P.I., Fayomi, O.S.I.
• Format: Article
• Language: English
• Subjects: Aluminium; Interface; Passive region; Ricinus communis; Thin film
• ISSN: 1452-3981; 1452-3981
• DOI: 10.1016/S1452-3981(23)16498-4

The assessment of Ricinus communis as corrosion inhibitor for aluminium alloy in 2M HCl and H3PO4 acid solution using gravimetric and potentiodynamic polarization techniques was investigated at 298K. The results revealed that Ricinus communis oil in 2M HCl and H3PO4-aluminium environment decreased the corrosion rate at various concentrations considered. Inhibitor efficiency (IE) as high as 75.75% at 20%v/v Ricinus communis addition and 82.35%/100%v/v Ricinus communis addition using gravimetric method were demonstrated in HCl and H3PO4 solution respectively. The IE from the potentiodynamic polarization method in both conditions was significantly enhanced. The scanning electron microscope (SEM) surface morphology of as-corroded uninhibited condition showed severe damage and pits formation than as-corroded inhibited conditions. The additions of Ricinus communis as corrosion inhibitor in each solution indicate higher potential value, IE and polarization resistance with decreased in current density. The methods for the corrosion assessment of the aluminium were in agreement and a mixed-type corrosion exist which obeyed Langmuir adsorption isotherms.