Electrochemical and Dissolution Behavior of the Ti-alloy VT-9 in H2SO4 Solution in the Presence of the Organic Inhibitor (2-Phenyl-4-[(E)-1-(4-solphanylanilino)methylyden]-1,3-oxazole-5(4H)-one

This investigation potentiodynamically evaluates the corrosion behavior of a high strength titanium alloy, VT-9, in 4 M sulfuric acid solution containing different concentrations (10, 20, 30 ppm) of the organic inhibitor, 2-phenyl-4-[(E)-1-(4- sulfanylanilino)methylidene]-1,3-oxazole-5(4H)-one (L-SH), at different temperatures (293, 303 and 313 ± 1 K). The open circuit potential values noted before and after each experiment varied appreciably with time. These values, in the presence of L-SH, were negative before polarization, but after completion of the experiment turned positive and remained stable over a long period of time. The cathodic current density values increased with increasing cathodic potential (more negative). The corrosion potential (Ecorr) increased remarkably with the addition of L-SH. The corrosion current densities (Icorr), critical current density (Icr), and passive current density (Ip) all decreased when L-SH was used. However, only the decrease in the Icorr with increasing amounts of inhibitor was significant compared to that of Icr and Ip. L-SH expanded the range of the passive potential. SEM micrographs and open circuit potential measurements revealed the formation of a uniform and protective film on the alloy surface in the presence of L-SH, which acted as an efficient inhibitor