Metal finishing Q&As since 1989

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Anode nickel selection

September 9, 2008

I am working on the selection of plating nickel among Ni squares, Ni rounds, Ni pellets, Ni chips, Ni discs, to name a few, and seeking expert recommendations. Here are some info I gathered.

Ni squares (99.9% purity) are often used, but there is some bridging issue in the anode basket which requires maintenance.

Ni rounds (99.9% purity) are a good choice but the price is a bit higher.

Ni pellets (produced from a nickel carbonyl process, ~10 mm diameter, 99.95% purity) are competitive in price, but seem less adopted in Ni plating.

Ni chips and Ni discs are likely derived from Ni pellets.

I hope to try Ni pellets for our Ni plating due to their price and easy handling, but heard some concern regarding their anode sludge level. I appreciate any comments/suggestions regarding the price, maintenance, anode sludge amount, plating operation pros/cons of various Ni anode materials.

John Shu
Plating shop employee - Mississauga, Canada

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September 10, 2008

You do not say what kind of nickel plating you are doing, sulfamate or bright. Nearly everybody will use sulfur depolarized for sulfamate Nickel.
Choice of anode material is somewhat driven by the size of the basket. It takes a large one to effectively use nickel squares that are 1 to 2 inches per side. Pellets work well for small to very small anodes. I used them in home made conforming anodes for ID plating.
What ever material that you use, you need appropriate cloth covers or anode bags. These need to be changed periodically and I always washed the crud off of the anode material , activated it and reused it. For electroforming, I would use a double bag system, one of fine dacron and one of napped poly.

James Watts
- Navarre, Florida

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James, thank you very much for the useful information.

I am selecting Ni anode for Watts bath. For cost reasons, non-SD nickel might be ok. Am considering 10-mm size Ni pellets. It seems such a size is smaller than either Ni sq or Ni rounds. Would the smaller Ni pellets generate more anode sludge than larger Ni pieces? I expect the use of Ni balls (pellets) might have less bridging in the basket thus reduce the maintenance frequency in anode basket repairing, however do worry about more anode sludge accumulation in the lower section of the anode basket with time, which may result in low plating rate and less uniform plating at the bottom. Am I right?

John Shu
- Mississauga, Ontario, Canada
September 12, 2008