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How to plate onto a nickel/tungsten substrate

2007

We are a New Zealand electroplating company. We are having trouble with a job that involves plating onto tungsten-nickel alloy parts.

The finishes required are black chrome and satin gold.

The problems we are having are adhesion failures (delamination off the substrate) and bright spots.

Any suggestions or information concerning cleaning and activation of tungsten-nickel alloy would be appreciated.

Simon Lee
Quality Manager Rigg Electroplating - Auckland, New Zealand

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We may tell you to use the process that you are currently using, so tell us what you are using, and someone may offer suggestions. James Watts - Navarre, Florida 2007 Also I forgot to include in the above: Any information on how to strip nickel off the tungsten alloy would also be appreciated. The alloy is 82% Tungsten and includes Nickel, Copper, Molybdenum and iron. When we strip it it becomes more porous presumably because some of the alloying nickel is also stripped out of the base metal. Simon Lee Rigg Electroplating - Auckland, New Zealand 2007

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James, I deliberately have not put the process we were using as my research so far has indicated it should have been totally unworkable.

We were correctly thoroughly precleaning the articles (trich, hot soak). After that we cathodically activated them in a mild acid Nickel activator, then they were nickel struck in a woods nickel (the low pH Watts Nickel strike made them go dark). Somehow this process produced results for a while.

However now my research indicates an anodic treatment in an alkaline solution; acid dip then a Chrome strike.

I am waiting for some samples to test with this.

So my main question at the moment is regarding the stripping of nickel off this alloy.

Simon Lee
- Auckland, New Zealand
2007