| 摘要 |
1438383 Colouring anodized Al and Al alloys RIKEN KEIKINZOKU KOGYO KK 5 June 1973 [6 June 1972 13 Nov 1972] 26633/73 Heading C7B A coloured oxide coating is formed on Al or Al alloy by forming an anodic oxide coating thereon and making the oxide coated Al or alloy one of a pair of electrodes in an electrolytic bath containing metal ions whilst providing alternately first and second direct currents (the same or different in value) flowing in opposite directions between the electrodes; the voltage when the anodized Al or alloy is cathodic being sufficient to produce electrolytic deposition of metal ions on the oxide coating, thereby colouring the coating. The anodizing may be effected previously, or may take place in the same bath as the colouring; the current reversal producing anodization when the Al is anodic and colouring when it is cathodic. The second electrode may be of carbon; or of Al or Al alloy, both electrodes then being provided with coloured oxidized coatings. Anodization and colouring may take place alternately with reversal of the current; or the value of anodic and cathodic currents may be chosen such that initially only anodization of a particular electrode takes place, and thereafter following a change in the values of the currents flowing, colouring of said electrode takes place. |
