Nickel anode questions?

A. The nickel anode material S and R are from Inco and have the following properties. S rounds have a small amount of sulfur to keep the anode active, which means the anode dissolves at a lower potential than pure nickel. The R-rounds are non-active anode material, which means you need some Chloride or Bromide to help dissolve the anode over a wide potential range. The D material is from Falconbridge and is the same as the S anode.

A. Yes-- S-Rounds or Falco D Crowns will work in a bath with chlorides. The voltage required will be lower with sulfur containing nickel, which provides a power savings. The nickel bars you refer to are not electro-nickel like the R and S Rounds, but rather cast or wrought nickel. I have no experience with this form, but my literature says that the carbon and silica would be higher than in electro-nickel.

 Thanks Don:

The waters not so muddy now! I'm starting to understand it.

A. S rounds definitely.

A. S-rounds contain a little sulfur to aid in anode corrosion, and they are generally for chloride-free or low chloride baths; N-pellets have no sulfur and are for most chloride baths, and will not properly dissolve in a chloride-free solution. Basically, pure nickel doesn't dissolve well except into high chloride baths, so sulfur is added to it.

It's not that it can't work, Ed. Rather, it's that successful, robust, equilibrium, plating involves getting control of a host of variables; it's like taming tigers, and as soon as you mix pellets in the anode basket, you've let another feral one into the cage.

If it's only a hobby, you can certainly do whatever you want, and it may well work 'good enough'. But part of becoming a gourmet cook is throwing away wilted lettuce rather than trying to sneak 'just a little' into each salad bowl.

(My partner Tom loves dubious metaphores; I'm sure I satisfied him with this one).

A. I wouldn't, Ed. The critical parameters of a nickel bath ought to be measurable without having to know it's past history. As far as I know, N-nickel won't 'ruin' a sulfamate nickel bath, just reduce it's concentration because not enough nickel is dissolving.

A. Rakesh,
The pellets should have an indication that they are Ni "S" pellets. If so, the sulfur is maintained at 2-2.5%. This is also true for Ni S rounds. Call your supplier to make sure the sulfur and purity of the nickel are the same. If they are, decide whether you want to mix them with the rounds in your anode baskets, or return them.

A. Hi, Rob. "Precisely the same" is a bit too strong a term to use for comparing proprietary products from different companies; but, yes, the "D Crowns" are sulfurized nickel like the "S Rounds".

Regards,

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A. R and S rounds are being replaced by Plating chips, P pellets and 1" x 1" chips substituted for R rounds.
S pellets are substitutes for S rounds. We have started using them and have not had any issues. Our lab associates have said they are easier to add to the baskets.

A. S Nickel rounds contain sulfur to help in the depolarisation of the nickel anode. This is very useful when using low chloride solutions such as those based on nickel sulphamate. If you can't get S-Ni, you must find an alternative to ensuring the anode is depolarised, so you may wihs to consider increasing the chloride content of your bath, but this will induce stress, so you will also need to add a stress reliever. I suggest you seek an alternative S-Ni supplier!

A. Hi Chance,

Similar phenomenon was not reported here yet but you may consider S-Pellets as replacement of S-Rounds if you doubt on D-Crowns.

Regards,
David

 It's been a few months now and I'm starting to get better results. The "S" pellets was an option I explored before I made the switch. Unfortunately it would require a lot of work to fabricate our anode baskets for such a small pellet and with the cost of mesh Ti sheet I wanted to avoid it if I could. The "d" crown deposit has leveled out with some adjustments to the chemistry. I reduced the pH from 4 to 3.8 and increased the hardener/leveler to the top end of recommended window of operation (11 g/l). Also ordered filter cartridges with a much larger micron size to increase agitation. Not the best deposit I've ever seen but much smoother now then it was. I'm making progress so I'm going to keep working at it. Thanks for the suggestions.

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Ed. note: If you wish to read more, thread 15218 is on essentially the same topic.