M. Tech. Chemical Engineering. / Discusses the effect of ferrous gluconate (FG) and zinc gluconate (ZG) as novel corrosion inhibitors on the corrosion rate of mild steel and aluminium alloy in 3.5% NaCl and 0.5 M H2SO4 media was investigated by electrochemical and weight loss techniques. The effect of inhibitor concentration was investigated. The concentration of these inhibitor ranges from 0.5 to 2.0% g/v at a temperature of 28OC. The synergetic effect of these inhibitors was also studied. High resolution scanning electron microscopy equipped with energy dispersive spectroscopy (HR-SEM/EDS) and Raman spectroscopy was used to characterize the surface morphology of the metals before and after corrosion. Experimental results revealed that ferrous gluconate and zinc gluconate in 3.5% NaCl and 0.5 M H2SO4 solution decreased the corrosion rate at the different concentrations studied. Maximum inhibition efficiency of 100% was achieved for mild steel at 0.5% g/v concentration of FG, 0.5% g/v concentration of ZG and 1.5% g/v synergetic of FG + ZG in 3.5% NaCl solution. Similarly, 100% inhibition efficiency was obtained for aluminium alloy at different media studied (3.5% NaCl and 0.5 M H2SO4). The experimental results obtained from potentiodynamic polarization method showed that the presence of FG and ZG in 3.5% NaCl and 0.5 M H2SO4 solutions decreases the corrosion current densities (icorr) and corrosion rates (CR), and increases the polarization resistance (Rp). It was observed that the inhibitor efficiency depends on the corrosive media, concentration of the inhibitor and the substrate material. The adsorption characteristics of FG and ZG were best described by the Langmuir and Freundlich isotherms. Good correlation exists between the results obtained from both polarization and weight loss methods.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:tut/oai:encore.tut.ac.za:d1000971 |
| Date | January 2013 |
| Creators | Sanni, Omotayo. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format |
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