Study of the complex of tungstate and benzotriazole as inhibitor for copper corrosion by photoelectrochemical and SERS methods

In this paper, photoelectrochemical method and SERS technique were firstly used to study synergistic effects of BTA and Na2WO4 for copper corrosion in 3% NaCl solution, and the mechanism of the synergistic effects was also st udied. It was shown that the inhibitive mechanisms of the complex of BTA an d Na2WO4 for copper corrosion have the same photoelectrochemical property a s BTA and Na2WO4. The photocurrent type transforming from p - type to n - t ype was due to the action of BTA with the potential positive scanning. Howe ver, the cathodic photocurrent value increasing evidently was due to the ac tion of Na2WO4 with the potential negative scanning. The result of SERS stu dy also showed that the complex synergistic effect is the same as that of t he results of photoelectrochemical studies. The results of SERS showed that both BTA and Na2WO4 play a role of inhibitive effect for copper corrosion. The action of Na2WO4 on copper is that it could produce a protective oxide s 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 cou ld make the film more density, therefore the inhibitive effects of the inhi bitor increased significantly.