Inhibition effect of Schiff base compounds T33, T45, T46 and T49 on aluminum corrosion in composite phase change material Na 2 HPO 4 •12H 2 O - Na 2 SO 4 •10H 2 O melting by electrochemical test

In the present paper, the inhibition effect of some Schiff base compounds on the corrosion of aluminum in a composite phase change materials of Na2HPO412H2O - Na2SO410H2O has been studied by Potentiodynamic polarization and Electrochemical impedance spectroscopy measurements. The Schiff base compounds are, (E)-3-(1-(2-(benzo[d]thiazol-2-yl) hydrazono)ethyl)-2, 6-dimethyl-2H-pyran-4-ol, (E)-N'-(1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)ethylidene)benzohydrazide, (E)-3-hydroxy-N'-(1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)ethylidene)-2-naphthohydrazide, and (E)-N'-(1-(4-hydroxy-2, 6-dimethyl-2H-pyran-3-yl)ethylidene) furan-2-carboximidhydrazide, which is represented as T33, T45, T46 and T49. This kind of compounds possess a common backbone of (E)-3-(1-hydrazonoethyl) -4-hydroxy-6-methyl-2H-pyran-2-one. The results showed that all the Schiff base compounds were able to inhibit the corrosion of Aluminum in composite phase change material Na2HPO412H2O - Na2SO410H2O. The inhibition efficiency followed the order T46 > T49 > T45 > T33 at the maximum inhibitor concentration of 0.009 M. The strongest inhibition effect of T46 is ascribed to its structure, which contains a hydroxyl group (-OH) in addition to the strong polarization property of the (E)-3-(1-hydrazonoethyl)-4-hydroxy-6-methyl-2H-pyran-2-one backbone.