Polyethylene glycol and polyvinyl alcohol as corrosion inhibitors for aluminium in acidic medium

The corrosion inhibition of aluminum in H2SO4 in the presence of polyethylene glycol (PEG) and polyvinyl alcohol (PVA) as inhibitors at 30-60 degrees C was studied using gravimetric, gasometric, and thermometric techniques. The inhibition efficiency (%I) increased with increase in concentration of the inhibitors. Increase in temperature increased the corrosion rate in the absence and presence of inhibitors but decreased the inhibition efficiency. Both PEG and PVA were found to obey Temkin adsorption isotherm at all concentrations and temperatures studied. Phenomenon of physical adsorption is proposed from the activation parameters obtained. Thermodynamic parameters reveal that the adsorption process is spontaneous. PEG was found to be a better inhibitor than PVA. (C) 2007 Wiley Periodicals, Inc.