New EN Technology for Aluminum

By Anonymous

Uyemura has introduced ANP, an electroless nickel technology engineered to improve plating onto aluminum. Plating electroless nickel on aluminum has been historically problematic and costly due to short bath life. While a normal EN bath containing 6-8 g/L of nickel can plate steel for six to eight metal turnovers (MTOs), plating onto aluminum reduces that bath life by about 50%. The typical failure mode is poor adhesion of the nickel to the aluminum, resulting in blisters or peeling when the aluminum is bent.

New aluminum plating technology is said to provide excellent adhesion.

Technology developed to address this problem of short bath life uses an alkaline nickel strike after zincating and before the regular plating bath. Drawbacks to that approach include extra tanks, process steps, and control over an additional plating bath. Failures have also been seen with nickel-to-nickel bonding. Strike baths also deposit magnetic nickel, thereby limiting their use to applications where magnetism is not a factor.

Uyemura, based in Sou thington, CT, says the ANP process for EN plating on aluminum substrates provides excellent aluminum adhesion through at least six MTOs. The process does not employ a strike and adds no additional steps compared to normal aluminum preparation double zincating.

Copyright Gardner Publications, Inc. Oct 2007

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