Carbonyl compounds as corrosion inhibitors for mild steel in HCl solutions

The paper gives an account of the performance of a number of carbonyl compounds as corrosion inhibitors of mild steel in 1–6 N solutions of hydrochloric acid. Furfuraldehyde seems to be the best inhibitor of all the carbonyl compounds investigated. Activation energies in the presence and absence of inhibitors have been evaluated. In cathodic protection studies furfuraldehyde reduces the protective current density considerably. The difference effect is positive in the absence and presence of inhibitors. Galvanostatic polarization data indicate that all these compounds are predominantly cathodic inhibitors. These substances are more effective in preventing the corrosion of aluminium alloys in hydrochloric acid solutions than the corrosion of mild steel.