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Nickel Strike before electroless nickel

 

I have heard of using a Nickel strike before coating the final layer of electroless nickel on to aluminum. What advantage does the nickel strike provide? Will it help with adhesion of the nickel to the substrate?

Brandon Hellenbrand
- Fairburn, GA, USA

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First of three simultaneous responses --  

Yes, an electrolytic nickel strike will help if the zincate is well done. There are EN formulations that are made specifically for a strike. Adhesion is markedly better for most platers. Drawback, strong ammonia smell and it (the solution)will break down at room temperature over a week or two. Work with your vendor, they can sell you inhibitors seperately and you can work the tank at a lower temperaature than in the specification (takes slightly longer) thus the solution will last a lot longer.

James Watts
- Navarre, Florida

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Second of three simultaneous responses --  

Yes utilizing an electroless nickel strike over zincate prior to electroless nickel eliminates the copper CYANIDE strike and water rinse following. The strike bath generally operates at about 90 degrees F, pH is about 9.5-10.0 if I recall. No problem with adhesion. We plated to a MIL Spec. A proprietary electroless vendor that supports this site should have a strike in their product line.

Bill Hemp
tech svc. w/ chemical supplier - Grand Rapids, Michigan

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Third of three simultaneous responses --  

What I believe you are referring to is an alkaline electroless nickel which is used as a strike prior to the plating of other electroless nickels on aluminum. This strike takes the place of using a zincate process. the formulations of the strike and the plate are different from both a chemical and engineering point of view. Without the strike or zincate you would get poor or little adhesion of the nickel to the aluminum.

Gene Packman
process supplier - Great Neck, New York