CORROSION INHIBITION OF COBALT WITH A THIN-FILM OF CU-BTA

Electrochemical techniques, ellipsometry and x-ray photoelectron spect roscopy were used to evaluate the use of benzotriazole, alone or in co mbination with boric acid/borate buffer and dilute copper sulfate for the protection of cobalt. The data indicate that in slightly alkaline solutions benzotriazole is a strong inhibitor for cobalt corrosion, wh ereas in water and neutral solutions it produces a barely measurable e ffect. In the presence of benzotriazole and Cu+2 ions, spontaneous red uction of copper ions leads to the formation of a thin film of Cu-BTA on the cobalt surf ace. This film acts as a corrosion protector that i s better than benzotriazole, with a significant reduction of the corro sion rate even during subsequent exposure to solutions without inhibit ors.