| 摘要 |
<p>1406591 Colouring anodized aluminium IONGRAF SA 7 Feb 1974 [21 Feb 1973] 5707/74 Heading C7B Anodized Al or Al alloy is coloured by electro-deposition by applying A.C. voltage between the Al (alloy) and a counter-electrode immersed in a stirred bath containing at least one Ni, Co and/or Cd salt preferably below 200 g/l, and at least one Cu and/or Sn salt below 2.5 g/l, the pH not exceeding 1.8 e.g. by adding H 2 SO 4 , and the A.C. voltage during each cycle being zero for a finite period. The salts may be sulphates. Stablilizing organic acids, e.g. sulphophthalic, phenolsulphonic and cresolsulphonic acids for Sn ions, may be added to the bath. The counter-electrode is preferably inert e.g. of graphite. Preferably the voltage is symmetrical and has a zero value for a total time corresponding to half a period: e.g. (1) half a wave followed by zero for half a period (2) wavy for a period followed by zero for a period, or (3) continuous positive and negative half periods separated by zeros for half a period.</p> |
