Abstract
The inhibition of the corrosion of mild steel in HC1 solution has been studied by the weight loss technique. The organic additives used as inhibitors; 2-hydroxy-l-naphthaldehyde-4-phenylsemicarbazone (HN) and 2,4-dihydroxylbenzaldehyde-4-phenylsemicarbazone (DB) inhibit the corrosion of mild steel to a reasonable extent by physisorption mechanism. The DB exhibited 71.82 percent efficiency while HN showed only 44.44 percent efficiency at the highest inhibitor concentration of 0.0005M at 303K. The compounds also obey Freundlich adsorption isotherm showing that the adsorption process was physical leading to multi-layer formation. Kinetic treatment of the results show first order process with respect to mild steel. The inhibitor DB was observed to be better than HN at both 303 and 313K. The differences in the inhibitory properties of the inhibitors have been explained in terms of the difference in their molecular structures.
NSTL