| 摘要 |
<p>1434701 Colouring anodized aluminium electrolytically ALCAN RESEARCH & DEVELOPMENT Ltd 19 Feb 1975 [20 Feb 1974] 7807/74 Heading C7B In the continuous electrolytic coloration of anodized Al strip using an acid electrolyte bath containing a manganate, tellurite or selenite or at least one salt of Co, Cu, Ni, Fe, Ag, Sn, Cr or Pb, by passing current between the strip and an electrode immersed in the bath and facing an anodized surface of the strip, the current is introduced into the strip through an unanodized area thereof. In Fig. 1, the strip is D.C. anodized (in e.g. H 2 SO 4 , oxalic acid or chromic acid) in cell 1 which contains immersed anodic and cathodic electrodes 4. After washing at 6, the strip is A.C. coloured in cell 7 using immersed electrodes 8, which connect to the strip via A.C. supply 9 and the anodizing anodes 4. Conductor 10 may either be replaced by variable resistance to give variable superimposed D.C. in the colouring bath, or may be removed, so removing the superimposed D.C. An alternative arrangement uses an external contact roller before the anodizing bath to introduce both the A.C. and D.C. Instead of superimposed D.C., an asymmetrical A.C. supply may be used. When the Al is anodized on one side only, either the process can be conducted on an already anodized strip, or the current can be introduced from an anodic sliding block contact, e.g. of graphite, in the anodizing bath. Electrolytes exemplified contain (1) NiSO 4 , (NH 4 ) 2 SO 4 , MgSO 4 and H 3 BO 3 at pH 5À7 or (2) CuSO 4 , MgSO 4 and H 2 SO 4 at pH 1À3.</p> |
