CORROSION AND CORROSION INHIBITION OF NICKEL IN HCLO4 SOLUTIONS USINGTHE EQCM TECHNIQUE

Application of the electrochemical quartz crystal microbalance (EQCM) to the study of metal corrosion and its inhibition is rather recent. A mong the advantages of this technique are its very high sensitivity an d the possibility of simultaneous mass variations and voltammogram rec ording. These characteristics suggest the use of the EQCM for research in very low corrosion rate conditions. This paper reports the results of EQCM measurements on the corrosion inhibition rates of Ni in 0.1 M HClO4, in the absence and presence of different inhibitors in free co rrosion conditions, for following inhibitors: acridine (A), benzyl qui nolinium chloride (BQCl), dodecyl quinolinium bromide (DDQBr), tributy lbenzyl ammonium iodide (TBNI) and potassium iodide (KI). The corrosio n rate was reduced considerably by KI and TBNI. DDQBr showed a good in hibitive efficiency, while BQCl had only a small effect, and A stimula ted corrosion of the Ni. Voltammograms at different scanning rates and the mass variation in the same solutions were recorded. Comparison of the current density and the mass changes provided the basis for a qua litative interpretation of the passivation of Ni and the mechanism of action of the different inhibitors.