A corrosion protecting film layer is formed on a non- passivating non- noble metal, such as cobalt, by placing the metal in a dilute solution of Cu.sup.+2 ions and benzotriazole (1 H-BTA). Exposure of the metal to a solution containing Cu.sup.+2 and 1 H-BTA results in a spontaneous interaction of Cu.sup.+2 and the metal to produce a film layer of Cu(I) BTA on the metal surface to create a permanent corrosion protection for the metal. A borate buffer, such as boric acid and a borate, can be added to the solution to adjust the pH of the solution to be in the range between 8 and 9.
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