In the following solution at 50 ° C for 10 min:
Potassium dichromate saturated solution 0.35 sulfuric acid (d = 1.84) 10
And then brush to the charcoal residue, washed with distilled water, 70 ° C under dry. This method is suitable for requests to reach the maximum peel strength of the place.
In the lead tank, the sulfuric acid concentration of 500g / l, anodizing 90s, voltage 6V, rinse with water, distilled water, 70 ° C dry, adhesive pieces for the anode, after treatment 5-10% chromium oxide solution Passivation for 20 min.
In the following solution at 85-90 ° C for 10min:
Oxalic acid 37 sulfuric acid (d = 1.84) 36 water 300
Washed with distilled water, with warm air dry.