INVESTIGATION OF INHIBITION EFFICIENCY OF KOLA NUT PLANT LEAVES EXTRACT ON CORROSION OF MILD STEEL IN HYDROCHLORIC ACID SOLUTION

Abstract

Evaluation of the inhibitive ability of kola nut leaves extract on the corrosion of mild steel in 1.0 M Hydrochloric acid solution using weight loss measurement at temperature ranges of 30 – 60oC was investigated. Chemical analysis of mild steel plate was carried out in National Metallurgical Development Centre (NMDC), Jos, Plateau State. The test media, plant extract and test coupons were prepared by standard methods. The coupons were immersed into the test media containing the extract in concentrations of 100, 300 and 500 ppm. After intervals of 7, 14, 21 and 28 days, the coupons were retrieved and percentage weight loss, corrosion rate and inhibition efficiencies of the extract were calculated. Kola Nut Leaves extract gave above 80% corrosion efficiency on the average depending on variables like temperatures, concentrations and exposure time. The corrosion rate varied between 1.586 to 0.654 x 10-3 mm/yr in the absence of the extract at all concentrations, temperature and exposure time respectively. Comparison of the inhibition efficiency of mild steel by Kola Nut extract and that of Miconazole Nitrate at 30oC shows favourable values of 80% and 85% respectively.