ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 52, Number 2
JKCSEZ 52(2)
April 20, 2008 

The effect of some furfural hydrazone derivatives (I -V) as corrosion inhibitors for C-steel in 3M H₃PO₄ solution in which M indicates mol/l has been studied using weight-loss and galvanostatic polarization techniques. A significant decrease in the corrosion rate of C-steel was observed in the presence of the investigated compounds. This study revealed that, the inhibition efficiency increases with increasing the inhibitor concentration, and the addition of iodide and thiocynate ions enhances it to a considerable extent. The effect of temperature on the corrosion behavior of C-steel was studied in the range from 30-60℃ with and without 5×10^-6 M investigated compounds using weight-loss method. Apparent activation corrosion energy (E_a^*) and other thermodynamic parameters for the corrosion process were calculated and discussed. The polarization measurements show that the investigated compounds act as mixed-type inhibitors, but the cathode is more polarized when an external current was applied. The adsorption of these compounds on the surface of C-steel in 3M H₃PO₄ obeys Frumkin’s adsorption isotherm. The mechanism of inhibition was discussed in the light of the chemical structure of the investigated compounds.