CORROSION INHIBITION OF AA6061 AND AA6063 ALLOY IN HYDROCHLORIC ACID MEDIA BY SCHIFF BASE COMPOUNDS

N, N'-bis (Salicylidene)-1, 4-Diaminophenelyne (SDP) and N, N'-bis (3-Methoxy Salicylidene)-1, 4 Diaminophenelyne (MSDP) were synthesized, and their molecular structure were determined by FT-IR and 1H NMR. The corrosion inhibitions of these compounds on AA6061 in 1M Hydrochloric acid were evaluated by weight loss method and scanning electron microscopic technique. The weight loss study showed that the inhibition efficiency of these compounds increases with increase in concentration and vary with solution temperature and immersion time. The various thermodynamic parameters were also calculated to investigate the mechanism of corrosion inhibition. The effectiveness of these inhibitors were in the order of MSDP> MDP. The adsorption of Schiff bases on AA6061and AA6063 alloy surface in acid obeyed Freundlich adsorption isotherm. The surface characteristics of inhibited and uninhibited alloy samples were investigated by scanning electron microscopy (SEM).