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Is bromine better than chlorine in nickel sulphamate baths?

Q. Since my retirement from my position as Manager of a Metalfinishing Dept. of a large Australian Company, I have been involved in consulting work in electroforming and also the repair of small and large moulds for the manufacturing industry. Recently I became involved in the question of the use of Nickel bromide as against Nickel chloride in Nickel sulphamate solutions for electroforming. I have graphs that the stress is somewhat lower with Nickel bromide than Nickel chloride. However I would appreciate some information in how much Nickel bromide has found use in electroforming. Some representative told a friend-electroformer everyone used it? Is this correct? Thanks for reply. Rob

Robbert B [last name deleted for privacy by Editor]
Private Consultant - Australia
1999

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Q. We recently fought through a serious de-wet issue in our plating process. We are plating 150 microinches of Sn over 100 microinches of Ni (plated) over silver (a cured paste). All plating is done automatically in an RFT plater. The product is a ceramic capacitor.

We basically turned our process over searching for answers and found two. Replacing the Ni bath, and bail and feed of the Ni bath. We are feeding Ni make-up which comes direct from the supplier ready to use. As soon as we scale back on the bail and feed we have de-wet. At this point we replace the Ni bath and we are off and running again. The bail and feed is at a rate that replaces the entire bath (100 liters) every four to five days.

It appears that we are either degrading or contaminating the Ni bath but we do not know how. We have performed analysis of the new and used chemicals and cannot find significant differences. The Ni bath we use is nickel sulfamate with a bromide anode activator, there are no organic additives. The process ran for a year with only normal, manual chemical addition maintenance, no feed and bleed or bail and feed.

Does anyone have any ideas of what I can look for to determine what is degrading and/or contaminating the Ni chemistry?

Rich Reifenheiser
- Monterrey Mexico
2000

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Q. 1. Nice to meet you! I am plating shop engineer of KOREA AIR FORCE.

2. I have a question for you.: I am holding your company produced sulfamate nickel plating solution. This solution only used or use with addition material. I don't know this solution make-up method. I wish you will send to me about make-up method. And if your know how send to me about nickel plating method on stainless steel I shall be grateful. I wait your message.

3. If your company agent would be in Korea. I wish response.

4. with best wishes.

JIN SOP .WOO
KOREA AIR FORCE - SOSAN IN KOREA
2001

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Q. We are using nickel sulphamate baths for electroforming. They contain chlorides to activate the anodes. How is bromine better than chlorine in activating the cathodes. We have problems with "E" nickel containing baths as the anodes tend to get passivated (though there is over 20 gpl chloride) and there is nickel depletion in the bath. Can replacing the chlorine with bromine improve on the situation? Secondly, what is the most common form to add bromine, is it nickel bromide--or some other chemical?

Nitin Kibe
Technical Director - Pune, Maharashtra, India
2003

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A. One of the things about sulphamate nickel is that if you use S-nickel, you (in theory) do not need chloride to polarise the anodes. Saying that, many sulphamate users like to add about 10 g/l nickel chloride, just to be on the safe side! Bromides will work in a similar way to chlorides and will not induce as much stress as the chloride. I would wonder why your anodes passivate, even with 20 g/l chloride; have a look at the anode bags - are they getting clogged with anode debris and limiting the movement of electrolyte? If so, give them a good clean. Trevor Crichton R&D practical scientist Chesham, Bucks, UK 2003 A. Hello Nitin: Many years ago, a manufacturer of Sulfamate Nickel processes in the U.S., recommended the use of their Liquid Nickel Bromide in a Sulfamate Nickel Bath. The Bromide ion was there for anode corrosion, similar to Chloride. However, their claim was that Nickel Bromide would not cause as much stress in the deposit as Nickel Chloride. I have never seen actual numbers or research work on this, however there were numerous shops using the Bromide with no apparent problems. Ed Budman [dec] - Pennsylvania With deep sadness we advise that our good friend Ed passed away Nov. 24, 2018 2003

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Multiple threads merged: please forgive chronology errors :-)

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March 24, 2010

Q. Hello,

I'm using nickel sulfamate electrolyte for electroforming. Actually I'm using S-Nickel anodes. Is it possible to use sulfur-free nickel if I add saccharin to protect the anodes going passive? If yes, what should be a useful saccharin concentration?

My electrolyte parameters are:

pH = 3,9 - 4,3
Cl = 6 - 10 g/l
H3BO3 = 40 g/l
Temp = 42 °C
current density = 6,5 A / dm2
bath it filtered.

The plating result is for my use very good. My goal is to recycle this electroformed material.

best regards

Frank Kirschner
Hobbyist - Stollberg, Germany

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Q. Thanks for your answer.

Yes, I know, but a higher chloride level is not acceptable due to too much stress.

Someone told me, it's possible to depolarize nickel by myself: Electrolyte: Nickel sulfamate with a little chloride and boric acid, pH around 4,0, anode: electrolyte nickel, as cathode a starter blank like V4A or thin nickel and then adding saccharin to the bath. At the cathode you will plate sulfur polarized nickel. The guy who told me has it made long time ago and made it very stable for a long time. But he didn't know the dose of Saccharin. S-Nickel has 0,026 percent of sulfur. What do you think?

Frank Kirschner [returning]
- Germany
March 25, 2010

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A. Frank Saccharin is not a depolariser, but as Ted says, you can use chloride. However, this will induce stress, so an option is to use nickel bromide as the depolariser; this will not induce so much stress, but it is not as good at depolarising as chloride. You can use your electroformed nickel as a source of nickel, but you will certainly need a depolariser in the bath if you are using a sulphamate system. The advantage of S-nickel is that it does not need depolarising. I am a little concerned about your high current density and low bath temperature; I would suggest that for good electroforming you should not exceed 45 ASF (4 A/dm2) and you should increase your bath temperature to about 55-60 °C. Do not go over 65-70 °C or the sulphamate can start to break down and induce stress. Alternatively, you can use the lower temperature but a much lower current density (say 20-25 ASF (2.5 A/dm2) Trevor Crichton R&D practical scientist Chesham, Bucks, UK March 25, 2010 A. You really need the sulfur depolarized anode in any nickel bath with a low chloride content. Saccharin, as Ted said, doesn't have an impact on the dissolution efficiency of the anode. Jon Barrows, MSF, EHSSC GOAD Company Independence, Missouri March 25, 2010

Q. We have inherited a nickel sulphamate solution for nickel electroforming. Rather than the usual make up of nickel sulphate, boric acid and nickel chloride, this solution uses nickel bromide in place of the chloride.

Can anybody suggest what type of nickel bromide this would be? I see prices range from $70 to $820 per 250 grams. Since the seller closed down, we can't ask anybody who worked there. Thanks in advance.

Darren Stevens
- Sydney Australia
August 18, 2020

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Q. Thank you, Robert. Our process doesn't particularly need bromide so we will make the switch as you suggest. I'v since contacted the former owner's chemist and she advises this is their proprietary formula and the nickel bromide is known as 'Additive B' which is not particularly expensive.

I understand they had massive problems with 'burn out' of the anode baskets even when the system has 'burn out protection' which perhaps they never used. Nobody else in the industry had burn out issues, even those using the identical PLC controlled electroforming systems so it could have been the bromide.

Eroding the titanium anode baskets is a big concern which leads to my next question. We need new baskets and were looking at stainless steel due to the high cost of titanium. What you would you think about that?

Darren Stevens
- Sydney, Australia.
August 23, 2020

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Q. Thank you, Robert. Stainless steel anode baskets were a recommendation from our colleague in Asia. I'm now wondering why he went out of business ...

Is the book you mentioned a book that you authored? If so, please let me know how I can buy a copy.

Darren Stevens
- Sydney, Australia
August 27, 2020