Anodes for nickel plating: Difference between squares and S-rounds

A. Hi Sally. Unfortunately, I think nickel-free ⇩ ^ ^sulfur-free anodes will quickly cause you trouble. They will not properly dissolve and will cause anode polarization, reduction in nickel concentration, etc.

Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. Hi Ted,
How are you? I hope OK and enjoying life.
In your answer you probably mean sulfur-free anodes and shouldn't we also include that at higher chloride levels both can be used?

Take Care,

A. Hello Sally,
The sulfur content of your Ni anode material will depend on your bath chemistry. If you have a chemistry that was previously dependent upon the sulfur content to aid dissolution, then switching to a Low sulfur content anode will create problems and vice versa. Many high chloride bright Ni plating baths operate with an "R" styled crown or pellet with a low concentration of sulfur (.0002) %wt. However low or non chloride baths such as Forming solutions require (.025) %wt for adequate anode dissolution to occur. 0.025 is what is commonly referred to as an "S" round or crown.
The "S", "D", "R" and other names start to get a bit confusing once you start to dig into different brands, so check with your chemistry supplier or refer to your bath's data and make up guide for what type of anode material needs to be used with your solution. Hope this helps. Good luck.

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A. Hi, Ranjith. The sulfur assists in anode corrosion, preventing the anodes from going passive. If you are doing conventional Watts' bright nickel plating, S rounds are the thing to use. If you are running a high chloride strike bath, the R Rounds may be more appropriate. If you are doing sulphamate electroforming, special techniques may be employed which use both types of anodes in separate compartments for the purpose of generating a controlled amount of "magic" stress reducer.

Please tell us about your nickel plating process. Thanks.

Regards,

A. Hi, Ranjith. For a conventional Watts' nickel bath (nickel sulphate / nickel chloride) the S-Rounds is usually used to promote anode dissolution / deter anode polarization.

Regards,

A. Hi, J. The theoretical problem is that the nickel will go passive and not dissolve into the plating solution. The result will be a rapid decline in nickel concentration, leading to plating inefficiency, rising pH, and a plating process out of control.

While it is possible to increase the chloride content to assist in anode dissolution, this raises other problems like excessive stress. It may be possible to run a Watts' nickel plating bath without sulfurized nickel anodes, but it is definitely the hard way :-)

Good luck.

Regards,

A. Hi, cousin Vu.

Both anode materials are type R, so they should not cause significant problems. Many shops use R squares.

Regards,

A. Hi Rajesh. I can't recall ever having seen the 100 mm x 100 mm (4" x 4") nickel squares. I would conjecture that they would cause bridging problems unless you are using very large anode baskets (wider than 4") -- but this is obviously supposition rather than experience.

Regards,

A. 10 by 10 are the same as 2.5 by 2.5 nickel; the only thing you will notice is that with 10 by 10 your baskets will be full with less material because they have big spaces between them, I like to use round pellets or nickel carbonyl method obtained nickel, they are more dense inside the baskets, and also is better to use type "s"; for me it gives better results because it has less tendency to passivate in the baskets. The other issue is that you have to compare the purity of the material.

They are produced the same way, the size of the cut is the only difference.

There is somebody that produces that nickel (pellets) in this page I saw his post one day offering this product.

A. Hi cousin Rajesh. If the vendor insists they are identical in composition and they're only cut to a different size, and you've received two responses here regarding the size, I don't think there is anything more to say. However, if they are from two different unknown vendors, then nobody can even hazard a guess. Good luck.

Regards,

A. Hi David. The "S" stands for sulfurized, and if you are able to continue obtaining sulfurized nickel, your life will be easier because regular nickel will go passive unless you add substantial chloride (and the problems it brings) to your electroforming bath.

Regards,

A. Hi Pat. The "S" and the "D" both refer to "sulfur depolarized" ... so they are intended for the same purpose and are essentially the same thing.

Regards,

A. Hi again Pat. I'm not a nickel plater and don't stay in contact with the suppliers of nickel anode material, so I'm no expert on this. Further, we can't suggest superiority of one proprietary over another (why?), but my understanding is that they are equivalent. You can google them both for the about their advantages and try to judge what is significant versus what is just sales pap. Good luck.

Regards,

Hi Pat,

One difference is D Crowns in button shape while S Pellets in ball shape. Last time S Pellets vendor also supply button shape S Rounds but obsolete already.


Regards,
David

A. Hi Pat,

I am transitioning our Ni plating baths from S rounds to D crowns. They are essentially the same as stated above just a slightly different shape. S rounds have been discontinued and replaced with D crowns. I believe S rounds were made in Canada and D crowns in Norway. I have never used a pellet shaped anode for Ni plating.

S-Rounds: Diameter = 25 mm Thickness = 6.5 mm (from TDS)

D-CROWNS: Hemispherical with a base diameter of 22 mm (from TDS)