In this paper, photoelectrochemical method and SERS technique were firstly used to study synergistic effects of BTA and NaWO4 for copper corrosion in 3% NaCl solution, and the mechanism of the synergistic effects was also studied. It was shown that the inhibitive mechanisms of the complex of BTA and NaWO4 for copper corrosion have the same photoelectrochemical property as BTA and NaWO4. The photocurrent type transforming from p-type to n-type was due to the action of BTA with the potential positive scanning. However, the cathodic photocurrent value increasing evidently was due to the action of Na2WO4 with the potential negative scanning . The result of SERS sutdy also showed that the complex synergistic effect is the same as that of the results of photoelectrochemical studies. The results of SERS showed that both BTA and NaWO4 plya a role of inhibitive effect for copper corrosion. The action of NaWO4 on copper is that is could produce a protective oxides film with copper on its surface, However for BTA, it could form Cu(Ⅰ) BTA polymer films on the surface of copper in order to diffusing on the surface. Because of the increasing of copper oxide, the Cu(Ⅰ) BTA polymer films could make the film more density, therefore the inhibitive effects of the inhibitor increased significantly.

Key words: TUNGSTATE, COPPER, ELECTRODE, CORROSION INHIBITORS, PHOTO-ELECTROCHEMISTRY, SYNERGISTIC EFFECT, SURFACE ENHANCED RAMAN SCATTERING