| 摘要 |
PURPOSE:To form a pattern having various densities on the surface of an Al hoop in the stage of coloring the Al hoop by continuous anode electrolysis and secondary electrolysis by masking partially the Al hoop during the secondary electrolysis and conducting locally electricity thereto. CONSTITUTION:An Al or Al alloy hoop 1 subjected to a pretreatment is introduced into a power feed cell 2 for secondary electrolysis and current is supplied from an AC power source 4 to an electrode 3. The hoop is then introduced into a power feed chamber 5 for anode electrolysis where electricity is conducted from a DC power source 10 to electrodes 11, 12, 13 to increase gradually the voltage. The hoop 1 is further introduced into a secondary electrolysis cell 14 where a rubber roll 15 is brought into tight contact with the hoop at about 90 deg. angle to effect electrolysis between the hoop and a carbon rod 16. A rugged pattern is preliminarily formed on the surface of the roll 15 so that an electrolyte introduces into the recesses to form a dark color in said recesses. A two-color pattern 18 having various densities is thus formed on the surface of the hoop 1.
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