| 摘要 |
A process for treating the surface of a metal substrate comprising a constituent metal selected from the group consisting of Cr, Cu, Mn, Mo, Ag, Au, Pt, Pd, Rh, Pb, Sn, Ni, Zn, in some cases Fe, and alloys of these metals. An anodic potential is applied to the metal surface in an electrolytic circuit comprising the metal surface, a cathode, and an electrolytic solution that is in contact with the metal surface and in electrically conductive communication with the cathode. The electrolytic solution may contain an electrolyte comprising anions of phosphate, phosphonate, phosphite, phosphinate, nitrate, borate, silicate, molybdate, tungstate, carboxylate, oxalate and combinations thereof. The anion may comprise a polymer having a pendent moiety selected from the group consisting of phosphate, phosphonate, phosphite, phosphinate, sulfate, sulfonate, carboxylate and combinations thereof. The potential applied to the circuit is such that the substrate is anodically oxidized and reacts with the anion to form a composition that imparts an enhanced property to the metal surface. Preferably, the pH of the electrolytic solution is less than about 6.0, the potential applied is between about 0.5 and about 20 volts, and the current density is between about 0.01 and 2 amps/dm2 of the geometric surface area of metal in contact with the electrolytic solution and is controlled such that nascent cations of said constituent metal produced by anodic oxidation of said constituent metal react with said anions at the metal surface without significant formation of any oxide or hydroxide of said constituent metal. |
| 主权项 |
1. A process for treating the surface of a non-ferrous metal substrate comprising a constituent metal selected from the group consisting of Cr, Cu, Sn, Ni, and alloys thereof, the method comprising:
applying an anodic potential to said metal surface in an electrolytic circuit comprising said metal surface, a cathode, and an aqueous electrolytic solution in contact with said metal surface and in electrically conductive communication with said cathode, said electrolytic solution containing an electrolyte comprising a compound having a hydrophobic carbon-carbon chain with hydrophilic anionic functional groups and another anion selected from the group consisting of phosphate, phosphonate, phosphite, phosphinate, nitrate, borate, silicate, molybdate, tungstate, carboxylate, oxalate and combinations thereof; and controlling the potential applied to said circuit between about 0.5 and about 3.0 volts and the current density between about 0.01 and about 2.0 A/dm2 of the geometric area of said metal surface in contact with said electrolytic solution such that a constituent metal of said substrate is anodically oxidized and reacts with said compound to form a composition at said surface that imparts an enhanced property to said surface; wherein the current density and voltage are controlled so that said composition is formed at said surface but no detectable increase in the thickness of any layer comprising an oxide or hydroxide of any of said constituent metals occurs during passage of current in said circuit. |
