Synergistic corrosion protection for galvanized steel in 3.0% NaCl solution by sodium gluconate and cationic surfactant

The influence of Sodium Gluconate (SG), cetyltrimethylammonium bromide (CTAB) and their mixture on galvanized steel corrosion in 3.0% NaCl solution was investigated by using electrochemical measurement coupled with scanning electron microscopy (SEM). The polarization measurements indicated that SG, CTAB and their mixture act as cathodic-type inhibitors. Indeed, a synergistic effect was found between SG and CTAB. In fact, the inhibition efficiency of the mixture reached 94% at 10(-3) M of SG with 2.74 x 10(-5) M of CTAB. In addition, this inhibition efficiency improved remarkably with immersion time and temperature. The SEM observations and energy dispersive X-ray (EDX) analysis indicated that the surface homogeneity increases with mixture addition. Finally, the thermodynamic parameters were determined and discussed. (c) 2016 Elsevier B.V. All rights reserved.