ELECTROCHEMICAL, SEM AND FTIR STUDY OF THE CORROSION INHIBITION OF JANUVIA FOR Zn IN HYDROCHLORIC ACID MEDIUM

Electrochemical, Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) were used to study the inhibitive action of Januvia for the corrosion of zinc in HCl. The result indicated that Januvia inhibited the corrosion of zinc in HCl by being adsorbed on the surface of the metal. Polarization data obtained suggest that Januvia blocks the actives sites for cathodic and anodic reaction, thereby protecting the metal against corrosion. The adsorption of Januvia on the surface of zinc was found to be spontaneous and occurred according to the mechanism of physical adsorption. Also, the adsorption characteristics of the inhibitor were best described by Temkin adsorption isotherm. From the FTIR results, it was discovered that some functional groups of the inhibitor after being adsorbed on the surface of the metal were missing; some were re-characterized by shifts in frequency of absorption while few new bonds were formed. The SEM images of inhibited strips obtained reveal the likely formation of a protective film. The use of Januvia as inhibitor for zinc corrosion is therefore advocated in this work.