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'''Electrolytically assisted pickling, activation and degreasing'''

Pickling can be enhanced by making the substrate anodic. The non-electrolytic pickling of metals is often followed by electrolytic activation to remove the remains of unwanted residues from the surface, such as oil and dirt, which remain trapped in the micro-roughness of the substrate surface. These are removed by the formation by electrolysis of H2 at the surface of the cathode and O2 gas at the surface of the anode. The basic composition of the solution is similar to alkaline degreasers, although the chemical concentration is generally twice as high. Wetting agents are omitted to prevent foaming; however, cyanides or other complexing-agents may be added to improve the activation of steel items. For normal applications, cyanide- and chelating-agent free electrolytes are sufficient. The solution lifetime is mainly determined by dilution through drag-in of rinse-water and drag-out of process solution. This process is not used in anodising.

''Source: BAT Surface Treatment of Metals and Plastic, Aug. 2006.''

 

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