Anti-tarnishing solution and a method for preventing tarnishing of copper or copper alloy

摘要

An anti-tarnishing solution for copper or copper alloy material which can produce a treated surface having outstanding heat resistance as well as anti-tarnishing effect in ordinary environment, with excellent adhesion to resin at low temperatures comprises a silane coupling agent and a metal nobler than copper or a salt of the metal as major constituents and water or an organic solvent, and further optionally comprising a pH buffering agent and/or surfactant. The anti-tarnishing treatment is carried out by dipping the copper or copper alloy in the anti-tarnishing solution or by sprinkling or spraying the solution over the object. The metal may be Ag, Au, Pt, Pd, Rh, Ru, or Os and the salt may be salt of these metals. Numerous different silanes may be used.