Synergistic effect of halide ions on the corrosion inhibition of aluminum in acidic medium by some polymers

The corrosion inhibition of aluminum in H2SO4 the presence of polyvinyl alcohol (PVA) and polyethylene glycol (PEG) and the effect of addition of halides (KCl, KBr, KI) was Studied using the hydrogen evolution technique at 30 and 40 degrees C. Inhibition efficiency (%I) increases with concentration of PVA and PEG-but With PEG having higher %I. The %I decrease with increase in temperature frorn 30 to 40 degrees C in the absence and presence of inhabitor and halides. PVA and PEG were found to obey Freundlish adsorption isotherm. Phenomenon of physical adsorption is proposed from the obtained E-a, A/G(ads), and Q(ads), Values obtained. The synergism parameters (S-1) obtained were found to be greater than unity for both PVA and PEG(1) which indicates that the enhanced inhibition efficiency caused by the addition of halides is only due to synergism. (c) 2006 Wiley, Periodicals, Inc.