Nickel Plating Brighteners: Everything to Know

A. 2,7-naphthalene-disulfonic acid

(pubchem.ncbi.nlm.nih.gov/compound/Naphthalene-2_7-disulfonic-acid)

A. Hi, Elena. That's a tough one because proprietary brighteners are a principal income source for most suppliers, and I think they will be reluctant to give much information about what components they use in making them. However, you might talk to the suppliers of nickel plating solutions that you can reach, and see what you find out.

Look under "Plating Processes, Nickel" in the "Products Finishing" Directory (ISSN-0032-9940/82), for a list of about 50 suppliers.

P.S. -- What exactly is PPS?

A. The Products Finishing Directory is a handbook published annually by Gardner Publications. It is inexpensive, about $10 or so. A library or bookstore should be able to provide availability info from the ISSN number I gave you. You may find copies of old editions from on-line bookstores, or contact Gardner Publications through pfonline.com

A. Try Enthone-Omi in Italy or anywhere else in Europe. They manufacture nickel brightener.

A. Hi Elena,

I have been watching this letter since it was first posted. I don't know what you do in Italy, but talking about brightener formulations openly in the USA is an absolute taboo. I mean, it took me years to say saccharin (gasp) in public (I still blush when I do that). I wasn't going to be the first, but since you told us what PPS is, I guess I could talk a little bit about nickel brighteners. There will probably be a cross-burning on my front pebbles tonight, but here goes:

I believe that propane sultone is a precursor in a pathway to the pyridinium compound you referred to in your last letter. But this has more to do with designing nickel brighteners than it does with formulating a practical nickel brightener. Many companies sell organics which function as Class I or Class II nickel brighteners and can be mixed right up in your sink. That's always been a fantasy for platers in these parts; buy the commodity chemicals for 1/100 the cost of buying proprietary additives from chemical houses.

I no longer work in formulating brighteners, do you sell organic chemicals? I'm still not sure what you can do with this information, not that it's any of my business.

Best Regards,

"Lookin' for a lover who won't blow my cover, she's so hard to find." -- The Eagles.

Wait 'til you see the ads in Metal Finishing magazine, Tom! There, right out in the open no less, a company called Seal Sands Chemicals is offering "A finer finish for nickel plating", PPS-OH-40% w/v. They go on to say this is 1-(2-Hydroxy-3-sulfopropyl)-pyridinium betaine, that it's pyridine-free, and that they also offer N-benzylniacin 24-26% w/v as well.

As you can see, Bert, we appended your inquiry to a thread wherein some organizations seem able to offer you such technology, and seem eager to do so. Good luck.

A. Sulfur-containing brighteners for nickel are the most common ones and they do not cause adhesion problems. Sulfur free systems are used mainly for corrosion reasons. You can find brighteners at any supply house for the metal finishing industry.Sara

A. Luis:

Cobalt salts were very popular Ni brighteners in the old days, especially for barrel applications. I don't believe anyone sells them as brighteners anymore, but you can buy cobalt sulphate or chloride and use low concentrations (~.01 g/l, if memory serves) to get a brightening effect (not as strong as with organic ones). You need to experiment.

Sara is right, though, organic brighteners if used properly should not cause adhesion problems.

Good luck, Berl

A. Hi, folks. Although it's true that sulfur-bearing brighteners should not cause adhesion problems in normal circumstances, organic brighteners can cause blistering problems at very high temperatures. And I suppose you could call a blister an area of non-adhesion :-)

My understanding is that sulfamate nickel (no added brighteners) does not have this problem, and is a good high temperature solution.

Regards,

A. Hi, Chris.

ASM's Metals Handbook Volume 5: Surface Engineering will tell you quite a bit about carriers, brighteners, and auxiliary brighteners in its Nickel Plating chapter.

We will be happy to print the names of any other published references anyone would like to contribute, but can't print actual formulations or technical data since this is the industry's most closely held trade secret and the anonymity of the internet could compromise them.

A. Dear Mr Ballew

The design and successful manufacture of Nickel Brighteners is a fairly long and tedious job taking up to a lifetime of experience to make a stable product that produces repeatable accurate results. You obviously wish to make your own Nickel brighteners for some undisclosed reasons.

However if you wish to assemble Nickel brighteners and have a requirement of, say, one to two thousand liters, it will be possible to help you with pre blended intermediates which are then mixed to produce a workable brightener system.

It is done by some very large plating shops that wish to economise on costs and control the quality material inputs themselves.

Kind Regards and Good luck.

A. You can formulate the nickel brighteners and additives by blending the intermediates available. There are various combinations to formulate the brightener and the choice depends upon the application, i.e., for barrel or vat, high speed (quick leveling) or the further topcoat required (gold / chrome). There are companies who can supply such intermediates.

A. Hi, Frank. It is true that you can use such additives as saccharin as carrier, 1,4-butyne 2-diol as an auxiliary brightener, and Thiourea ⇦ this on eBay or Amazon [affil links] as primary brightener, with Johnson's baby shampoo as the anti-pit. Further info about these generic additives and the roles of the individual components is in the ASM Metals Handbook Volume 5. It's good reading.

But maybe you've already been offered professional advice but didn't want to hear it; professionals use proprietary products not because they are too dumb to mix their own additives, but because they are too smart to :-)

These generic additives represent returning to the 1940's. Research scientists for the major suppliers have spent their entire careers developing appropriate additives, and their employers have paid their wages for all those years, and they are recouping that investment by selling these proprietary additives by the gallon. That's why no one will say exactly what they are.

But it's not so that you don't learn the info, because you probably would not be able to put it to use anyway. Making brighteners isn't about mixing, it's about synthesizing organic materials from their precursors, like synthesizing plastics from crude oil. It's secret so their major competitors who can afford synthesis laboratories don't compete against them.

You need to either hand polish the nickel as you are doing (and which was done in the old days) or to buy proprietary processes that enable self-leveling. Good luck!

A. Formaldehyde is not harmful for nickel plating solutions yet it cannot be used as a brightener.

A. Hi, cousin Ahmet. ASM Handbook Vol. 5 has an excellent chapter on nickel plating and the role of the various generic brighteners and addition agents including formaldehyde.

Good luck.

Regards,

A. Hi, Shahin. Hello Mohammad.

While there is certainly nothing wrong with your asking, you will need to ask known associates or to inquire in the published literature. The formulation of nickel brighteners has been the electroplating industry's most tightly held trade secret for many decades. The relative anonymity of the internet is at odds with the protection of trade secrets because there is no practical way for us to know the posters, their vested interests, whether names have been spoofed, etc. A disgruntled employee could deliberately leak his employer's trade secrets under an alias to put him out of business for spite.

Again if anyone wants to reference published literature on the subject, we're happy to include the name of the original literature source on this page! But printing hints from essentially anonymous party A, augmented by information filled in by anonymous party B, and procedures from party C, can be tantamount to group sourcing industrial espionage :-) Thank you for your understanding of why we can't post such dialogs.

Regards,

A. One place that I've been using for some good basic knowledge for awhile is http://www.substech.com/

They have several very informative articles on electroplating and some basic information on the common non-proprietary brighteners used.

There are several book samples available through Google books that also list the common chemical brighteners and concentrations they are commonly used in:
http://books.google.com/books?id=U6RPpeVFmjYC&printsec=frontcover&num=100#v=onepage&q&f=false

I can provide further information and literature that is publicly available.

Neither of these are strict 'how-to' guides, but they will put you on the right track.

Thanks, Mark. Dennis & Such's Nickel and Chromium Plating [on Amazon affil links] is the book extracted in the google link you offered, and it is indeed a great source of generic info on nickel plating additives!

Regards,

A. As an additional note you can usually get away with using a sodium based salt of the acid in place of the acid itself. So if in your reading you come across Benzene Sulphonic Acid, you can use sodium benzenesulfonate or nickel benzenesulfonate in a pinch. This is an EXAMPLE, not an answer. Your answer is going to depend on the specific setup you have, there are no quick or general answers.

You've GOT to know your chemistry if you want good results from any plating. I do this as a hobby and I've learned WAY more than I ever expected. If you aren't willing to spend days and weeks doing the reading and research, or you just want a quick simple setup without learning the ins and outs you can get a hobby plating kit that will produce reasonable results for pretty cheap.

Knowing the ins and outs of the system and what is happening is why the guys here that share their knowledge are so impressive to me and why I read so much.

SCIENCE!

A. Hello Mani,
Acetylenic compounds for semi bright solutions are in wide use now. I am not a chemist so I can't give you formulations. Your best bet is to contact your Nickel bath supplier, and tell them what you need. They may have a brightener system that can be "slide converted" into your bath. Good Luck!

A. Mani,
Sarah's response was to a question Luis had. Anyway, her advice and mine to contact your Nickel bath supplier would be your best bet.

A. Dear Mr. Bhattar,

All bright Nickel plating additives are sulfur-containing. The brightness/luster is because of sulfur inclusion in deposit.

"sulfur Free" Nickel deposit is semi-bright in its appearance and almost No sulfur. Due to this such deposit is passive and nobler than bright deposit. sulfur free deposit forms a base coat in multi-Layered Nickel deposit, exhibiting higher corrosion resistance.

As far as I understand, commercially there is no such thing as sulfur free bright Nickel.

Regards,

A. Hi Ritesh. Please see the applicable chapter of Volume 5 of the ASM Metals Handbook as suggested if you haven't yet, as well as Dennis & Such. And try the websites suggested by Marc Banks.

Brighteners aren't made by mixing generic chemicals; are you interested in the approach suggested by Asif Nurie and Anil Basrani of blending from intermediates furnished by others?

I'm not trying to give you a hard time, but designing brightener molecules and other additive molecules from scratch via organic synthesis from precursors is a difficult subject even for those of vast experience, which I don't have -- I wouldn't know how to begin :-)

Best of luck. Regards,