| 摘要 |
Aluminium or aluminium base alloy members are anodized by passing such a member through a cooling chamber and passing the cooled member and a sulphuric acid electrolyte in opposite directions through an anodizing bath, the bath being maintained at a temperature not exceeding 20 DEG C. and anodizing being effected at a current density not less than 20 e.g. 80 to 120 amps./sq.dm. Preferably the anodizing bath is constructed in the shape of a Venturi tube, the electrolyte being recirculated. When anodizing a strip the strip may divide the anodizing bath into two chambers each containing an electrode, guides being provided so that the resistance of the electrolyte in each chamber is greater than the resistance of the strip, whereby if both the electrodes are cathodes and the strip acts as anode both sides of the strip are anodized while if one electrode is an anode and the other a cathode with the strip not electrically connected only one side of it is anodized. The pre-cooling of the strip may be effected with commerical solid CO2. |
