Abstract
Electrochemical measurements have been used to study the influence of temperature on corrosion and inhibitive effects of 4-methyl acetophenone thiosemicarbazone and 4-methoxy acetophenone thiosemicarbazone on the corrosion of Fe78B13Si9 metallic glass in 0.2 M Na2SO4 between 293 and 333K. A good agreement between the data obtained by polarization and impedance measurements was found. A rise in temperature associated with an increase in i(corr) and 1/R-ct values and decrease in the inhibition efficiency suggest a physical adsorption model for the corrosion processes. The results show that these compounds almost inhibit the iron-based glassy alloy corrosion at elevated temperatures. The difference in the inhibition behavior of the two compounds is explained in terms of the difference in the electron densities on the centers of adsorption in the thiosemicarbazone molecules. Thermodynamic parameters, Delta E-opp, Delta H*and Delta S*, have been calculated and are discussed.