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Electroplate vs EN

2007

We are trying to gather some market data and information about electroplating and EN (electroless nickel) process so that we can decide which process is better for pure Ni coating process. The main objective with these coatings is corrosion resistance and good adhesion. Is it possible to put coating of 40-50 microns of pure Ni coating on low carbon steel with either process and if yes what is the average time that takes for it (plating rate)? Will either process produce any toxic waste and is waste water treatment or solid waste treatment required with it? What is the typical hours obtained during an ASTM B117 test with these two process with 50 micron Ni coating?
Any information on data such as total capital investment involved, total energy consumption, environmental cost involved for both process of the same size will be helpful. I am also looking for a comparison on uniformity, appearance, plating adhesion and other properties.
I know this is a long question, but I don't know about a better source to ask these questions.

Prat George
Metallurgist - Baton Rouge, Louisiana

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OK - I have a short question which should be as easily answered as your question: What are the winning Power Ball numbers for tonight's lottery drawing? You see, it's easy to post a question that you're not real likely to get an honest, complete answer on. I'll try a couple of basic starter responses: (1) if you need pure nickel, electroless nickel won't work as is always deposits a nickel rich alloy that incorporates at least some of the reducing agent be it boron or phosphide. (2) plating rates for electroplated nickel vs. electroless nickel are both upwards of 1 mil (25 microns) per hour so close - electroplated rates more easily adjusted. (3) Electroless nickel at 50 microns (~2 mils) will be smooth whereas electroplated nickel will likely have some nodules associated with it and be far less uniform in thickness distribution. (4) installation cost dependent on size and quantity of parts to be plated - bare minimum for either would be $50,000 but upwards to $1/2M if parts are sizeable (where 6-foot tanks or better required). Given your locale, I'm guessing you're in the chemical processing or petro industry and there are plenty of existing installations capable to doing this without requiring capital outlay and generating all the associated hazardous waste and heavy metal laden wastewater that must be continuously waste treated. Lastly, do you have my winning numbers yet?

Milt Stevenson, Jr.
Syracuse, New York
2007

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In thanks for the informative answer, a lottery ticket is in the mail, Milt. I'm not sure it's the winner, but we tried -- and, hey, ya never know.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

You are right, too many questions and too little previous knowledge about the subject. I suggest that you get a plating book.

Guillermo Marrufo
Monterrey, NL, Mexico
2007

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First of two simultaneous responses --

Milt, Thank you for your response. Guillermo, you are correct in saying that I have too little previous knowledge, but I don't want to consult a text book because it mainly deals with theory and not what really happens in an industry. As I said I am not trying to open a plating shop or anything similar (I don't think I will ever work on electroplating or EN), just wanted to compare the two process and who knows there may be a better process out there than the two. The valuable experience you and others have gained over the years cannot be found in any text book (at least from the ones I know). I know it is a bit of injustice to know the things in one minute from someone who has spent years in understanding these things. So please bear with me if I am looking for too much information :) and unfortunately Google doesn't provide answers to all your questions.
Thanks Ted for the lottery ticket.

Prat George
- Baton Rouge, Louisiana
2007

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Second of two simultaneous responses -- 2007

Quite right, Milt except that EN does not contain some of the reducing agent. It is in fact an alloy containing between about 2 and 14% of phosphorus. The properties vary with the composition and can be quite different to pure nickel. There is a boron version but it is rarely seen.
As for electroplated nickel - it depends what you mean by pure.
Corrosion resistance depends on what is doing the corroding.
EN is widely used in the chemical, marine and oil industries but it is much more expensive than electrolytic.

The question about toxic waste indicates that the company has no in-house knowledge of plating.

I would advise discussing the detailed requirements with a local plating shop. They can answer the questions, give costings and comply with any waste regulations that apply.

Geoff Smith
Hampshire, England

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2007

Thanks, Geoff -- and everyone -- for the input. I don't quite agree, however, that referring him to a plating shop is the answer. Some shops offer only EN or only electrolytic nickel, and it would be sort of like asking the local BMW dealer to advise whether a BMW or Lexus is best. And if the shop does offer both, it still isn't fair to ask them to choose the coating, and thereby accept responsibility for the design if it turns out to not have been a good idea. The product designer rather than the plating shop is responsible for product design.

I think that Milt's introduction, augmented by Geoff's explanations, and followed by Guillermo's advice to get a book about it is the best path short of retaining a finishing consultant to help with the product design. But, to put the monkey back on Mr. George's back, I'll add that if he would tell us the actual product he is trying to design and the operating environment it would see, we could probably offer advice that is more targeted. Thanks all!

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