Copper Plating of steel wire

A. Hi Beryl. Plating is a reasonably complex process,and so is drawing. People will try to help you but will need a fair amount of detail, not just that the coating looks pale.

What is the specified thickness of the plating, and is it up to spec? Is the color saturation a part of the quality specification? You say it's pale "thus" there is a quality problem. Is the plating satisfactory in all other ways? Is the copper electroplating bath sulphate or fluoborate or cyanide-based or something else? Thanks!
Good luck.

A. Hi, Anil

You can try about 12% copper sulphate ⇦this on eBay or Amazon [affil links] crystals and 1/2 to 3/4 ounce per gallon of sulfuric acid as a starting point. I understand that copper coating of MIG wire is dead easy in principle; but the world is very quality conscious today, wanting an extremely thin, adherent and pore-free copper coating on MIG wire, and it can be quite a long way from simple copper coating to a very high quality copper coating. The solution probably requires proprietary additives.

I am not from the welding wire industry, but I am under the impression that MIG wire utilized an immersion plating deposit rather than electroplating. Good luck.

Regards,

A. Acid copper cannot be plated directly over steel must be over some type of coating due to potential.

 Hi, folks.

I may be in error, but I thought the copper coating on steel MIG wire is an immersion deposit. I'm not suggesting copper sulphate electrodeposition directly on steel, as I agree that you will usually get poor adhesion.

Regards,

A. Yes, I can be wrong, I am not sure if an immersion deposit will work! So my answer can mislead some readers! I'm sorry I just wanted to help.

But what Mr Anil says, look pretty near to what happens when you try to plate directly over plain steel and you get an immersion deposit which doesn't have good adhesion.

I talk about acid copper because the topic talks about copper sulphate and a rectifier.

copper sulphate + rectifier = looks like Acid copper

But if you prepare a solution of copper sulphate and immerse iron or steel in it you get an immersion deposit.

Is there an immersion deposit that achieves a good adhesion coating?

A. Immersion deposits, if properly controlled are adherent. The clue is to reduce their concentration and limit immersion time to avoid attack to the substrate. Alternatively, if thicker plate is desired, diluted alkaline copper (either cyanide or non-cyanide) is suitable for deposition directly on iron alloys followed by a conventional copper plate.

A. Sorry, Masih, but I'm not finding that word anywhere -- and it's possible that the spelling has become corrupted. But it doesn't sound like it's from a generic chemical naming scheme; it sounds like you are right that it is a proprietary chemical trade name.

Perhaps the way forward is to contact suppliers who offer addition agents and ask them for their adhesion-improving addition agents rather than "ADACID-CU" specifically? I find that googling the search term "mig immersion copper addition agent" leads to a number of papers on the subject. Good luck!

Regards,

A. Hi Ashok. Can you please clarify for us what you are doing? Are you trying to simply immersion deposit copper on this wire when you say "ordinary dipping" or are you trying to electroplate on it? Is there any specification for the copper sulphate solution (such as concentration or pH)? Thanks.

Regards,

A. Hi Amarnath. You can't get a coating of even 1% of that thickness by immersion plating; you'll need to do electroplating. And you won't be able to electroplate directly onto steel wire from a copper sulphate solution. The simplest answer is probably a thin flash of nickel electroplating followed by 200 microns of copper plated from a copper sulphate bath (it sounds like you are not talking about MIG wire, but a different application).

Regards,

A. Hello,
The copper coating done on MIG welding wires is a loosely adherent Acid copper sulphate Coating with an immersion time of 2-3 seconds and a film thickness of 0.1-0.3 microns. The adherence is further enhanced in the wire drawing die post copper plating referred to as skin pass.

I hope the plating experts will have something to add now.

A. AFAIK, there is no standard test. Try winding the wire about it's own diameter, and then examine under a microscope. No peeling or lifting, it is probably okay.

A. Typically immersion coppering baths contain proprietary additives to improve adhesion, level the deposit, and obtain brightness. (There are a number of other functions that the proprietary additives provide, but it is not worth going into excessive or extensive detail here.)

A standard test would be a tape test. While typically the tape test is used on a cross-hatched flat substrate, for wire this is unnecessary.

A. Hi cousin sakthi. Your question is a bit vague for me. Are you asking what the thickness ought to be according to some standard, or are you asking for a dissolution or micrograph destructive testing method to reverse engineer a sample of a competitor's product, or are you looking for a continuous non-destructive inspection method during production (I personally don't know if that's possible)? Sorry, but it's very hard to understand a question and make fast progress if you don't tell us your situation. Thanks!

Regards,