Process for continuous electrodeposition of chromium metal and chromium oxide on metal surfaces
AssigneeCentro Sviluppo Materiali S.p.A.
InventorsSanta Alota, Vincenzo Ferrari, Massimo Memmi, Leonardo Pacelli, Susanna Ramundo
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Abstract
In the continuous electrodeposition of chromium metal and chromium oxide on metal surfaces the codeposition of chromium and its oxide, inert and insoluble, is obtained from the same bath and at high current density, by using a number of cycles of impressed cathodic current and defined ranges of electrolyte velocities in the deposition cell. In this manner a product is obtained wherein a specific quantitative relationship between chromium metal and chromium oxide ensures corrosion resistance superior to that obtainable in known products.
Claims9
Process for continuous electrodeposition of chromium metal and trivalent chromium oxide on metal surfaces, in which a continuous metal body is continuously immersed in an electrolyte, that is strongly acid due to the presence of chromic acid, contained in at least one electrolytic cell in which said metal body acts as cathode, characterized in that said metal body is subjected to an electrolytic cathodic treatment comprising at least three successive pulses of current with a density of at least 50 A/dm.sup.2, while it is immersed in said electrolyte that has a pH of less than 3 and a velocity of over 0.5 m/s.
Dependencies are inferred from the claim text.