ALUMINIUM PRE-TREATMENT

ALU-ZINCATE is a cyanide-free dilute zincate process that is especially designed for plating nickel or electroless nickel on aluminium alloys. ALU-ZINCATE removes aluminium oxide and applies a thin zinc film on the aluminium alloy by immersion to prevent its reoxidation. This film can also be electroplated with copper, nickel and certain other electrolytic processes.

The dilute ALU-ZINCATE solution has a water-like viscosity that rapidly penetrates the water film present on the cleaned aluminium. This produces a denser, more uniform zinc film than found with conventional zincates. This film has improved adhesion to the aluminium, helping to ensure excellent adhesion of the subsequent plate.

The dilute ALU-ZINCATE solution easily penetrates into blind holes, crevices, screw threads, grooves and other inaccessible areas which have been troublesome to plate using conventional, concentrated zincate baths. On large, flat areas of aluminium sheet, the dilute bath produces a uniform zinc deposit instead of the streaked, uneven coating often obtained from the viscous, concentrated zincate solutions.

When work is removed from ALU-ZINCATE, the thin liquid drains readily from the most complicated parts, thereby keeping drag-out losses to a minimum. The thin film of solution which remains rinses off rapidly in a cold water rinse, and the transfer time to the rinse tank is less critical. It is relatively easy to flush the dilute zincate solution from pores in castings and from other areas which tend to entrap solution, thus minimising carry-over of the zincate into subsequent plating baths. Also, the ease of rinsing greatly reduces the chance of blistering the subsequent plate on porous castings.