Effect of some polymeric materials on the corrosion behaviour of tin in succinic acid solution

The anodic behaviour and corrosion of tin in various concentrations (0.05-0.7M) of succinic acid were studied using cyclic voltammetry. The potentiodynamic anodic polarization curves exhibit active/passive transition. The active dissolution of tin involves one anodic peak. The cathodic curve exhibits one cathodic peak corresponding to the reduction of the passive layer. The ratio of the anodic charge/cathodic charge is more than unity indicating that the passive layer is very thin and the dissolution products are mainly soluble species. Additions of some polyethylene glycols to the succinic acid solution decrease the anodic peak current and shift the peak potential in the negative direction. These changes depend on the concentration and molecular weight of the polyethylene glycol added. The effect of the inhibitors decreases in the following order: (PEG)(6000) > (PEG)(4000) > (PEG)(1200). The inhibition efficiency decreases with increase in temperature, suggesting physical adsorption.