Inhibition effect of acalypha wilkesiana leaf extract on pitting corrosion of ferritic stainless steel in acidic medium

Author: 
Onyinyechi Pauline Elenwo, Israel O, Owate and Michael C, Onyeaju

The study examined the possibilityof using extract ofAcalypha wilkesiana (AW)leafas green inhibitor for ferritic stainless steel (FSS).This was obtained in 0.5 M hydrochloric acid using gravimetric and potentiodynamic polarization (Tafel plots). The inhibitor, temperature and time concentration ranged from 0–10 percent v / v at 2 percent v / v interval to 30–60 ° C at 10 ° C interval at 3-18 days within a space of three days.Qualitative and quantitative analysis and Fourier Transforms Infrared (FTIR) Spectroscopy technique were used to characterize the sample. Scanning electron microscope (SEM) was used to analyze the sample surface morphology before, during and after testing. The findings showed that the corrosion rate increased with an rise in temperature and decreased with an rise in inhibitor concentration and time and acquired a peak inhibition effectiveness of 91.16 percent at an optimum 8 percent v / v concentration. The coupon's SEM without extract on the surface was rough, serious pits, cracks, and intermetallic dissolution occurred. There was an enhancement with a soft green inhibitor on the surface morphology of ferritic stainless steel. The adsorption and physisorption in nature of the extract obeysLangmuir adsorption isotherm. The inhibition effectiveness values acquired are well above a good inhibitor's minimum acceptable threshold of 70 percent. Therefore, the Acalypha wilkesiana (AW) extract was very efficient in inhibiting FSS corrosion in acidic medium.

Paper No: 
2671