Process for obtaining a range of colors of the visible spectrum using electrolysis on anodized aluminium

A process for obtaining a range of colors of the visible spectrum using electrolysis on anodized aluminum, comprising a first phase to form an anodic film which comprises a barrier film, a second phase to modify the barrier film and a third phase to deposit metallic particles on the barrier film, wherein:

• a thickness in excess of 0.3 .mu.m is obtained during the first phase of formation of the anodic film;
• the second phase includes electrolytic modification of a crystalline lattice of the barrier film which is carried out in an electrolyte, applying a voltage and a current density;
• and
• the third phase is carried out by an electrolytic deposition of metallic particles in order to increase internal reflections under a deposit of metallic particles, and wherein
• the electrolyte used in said electrolytic modification of the crystalline lattice of the barrier film has a dissolving power in aluminum oxide equivalent to a solution of sulphuric acid at a concentration of less than 12 q/l and at room temperature in a range between 20.degree. and 25.degree. C.;
• and
• wherein said voltage in said second phase includes peak voltages of positive and negative semi-cycles of an AC-Complex current applied of less than 7 volts.

A process for obtaining a range of colors of the visible spectrum using electrolysis on anodized aluminum, wherein in order to obtain a white-opaque color, the process comprises two phases wherein:

• at the first phase an anodic film which comprises a barrier film is formed having a thickness in excess of 0.3 .mu.m;
• and
• at the second phase a crystalline lattice of the barrier film is electrolytically modified in an electrolyte, applying a voltage and a current density and wherein:
• the electrolyte used in said electrolytic modification has a dissolving power in aluminum oxide equivalent to a solution of sulphuric acid at a concentration of less than 12 g/l and at room temperature in a range between 20.degree. and 25.degree. C.;
• and wherein
• in order to obtain a white-opaque color, the process comprises said two phases and the voltage applied in said electrolytic modification is below 5 volts of a complex alternating current.