# Multi-metal Electroplating solution



## rolynd (Jun 13, 2015)

Stumbled upon this patent lately http://www.google.com/patents/US20050230264

It claims the suggested solution could be used to plate a multitude of different metals upon different substrates. The interesting thing is , there are no additional metal salts required the deposited metal solely comes from the dissolved anode.
Patent claims this works for brass, copper, nickle, zinc, lead, steel, iron, silver , gold etc.
A further search on this brought up the following youtube vid, I dont fully agree on his "food additives" and "totally non toxic" atitude, oxalic acid is not to be considered non-toxic, but at least his plating of copper on SS seemed to be nice and shiny (which with a standard acidic copper electrolyte is not achievable) and did surprise me.
the comments also indicated it works good for silver. 

https://youtu.be/lyhQ7n5w_KA


since the main component is oxalic acid as a complexing agent we are dealing with mostly oxalates here. AFAIK silver oxalate is dangerous, (well, as long as in solution, no hazard) but if you were to evaporate to dry silver oxalate could pose a danger... I am also always hesitant if ammonium is mentioned together with silver salt solutions...

I am inclined to test this ,but before I expose myself to unwanted dangers ,its always a good idea to do some research and I wanted to tap into the combined knowledge thats presented here. 

I am not very much interested in base metal plating but if this could be used for silver- or even goldplating with at least equal success as the cyanide free electrolytes that are avaliable now it would be worth a shot. Cyanide bases electrolytes are still the best in terms of quality of the deposit but much too dangerous to deal with on a non-professional scale. I have tried several products which are commercially avaliable for the public with mixed results, some better, some worse but all of them were far from cheap. From my knowledge the cyanide free silver and gold electrolytes are based on thiosulphate or pyrrophosphates as complexing agents. Using oxalates is a new approach.

This one sounds almost too good to be true and things like that usually are...but if it were totally useless the guy wouldn`t have issued a patent at first...


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## goldsilverpro (Jun 13, 2015)

rolynd said:


> Stumbled upon this patent lately http://www.google.com/patents/US20050230264
> 
> It claims the suggested solution could be used to plate a multitude of different metals upon different substrates. The interesting thing is , there are no additional metal salts required the deposited metal solely comes from the dissolved anode.
> Patent claims this works for brass, copper, nickle, zinc, lead, steel, iron, silver , gold etc.
> ...


Without an appropriate initial concentration of metal ions in the solution to start, the plating efficiency of the bath would be close to zero. This is proven by the super thin copper deposit in the video. The reason it's bright and shiny is that you are seeing the shiny stainless through the copper.

For this reason only, it's a worthless patent not worth a second glance.


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## 4metals (Jun 13, 2015)

As a system for decorative electroplating I agree with Chris but what about as a copper plating bath for making pure copper from anodes with low concentrations of PM's? 

A lot of things will influence its benefit as a copper refining cell. First will be the actual rate it can deposit pure copper at the cathode, second will be wether impurities in the anode carry over to the cathode rather than reporting to the anode slimes, and finally how low the metals remaining in solution when you switch to a dummy anode to remove can actually go. ( for it to be truly non hazardous, the only true value of the idea, it will have to completely strip the solution of metals). 

May be worth playing with in my spare time ( of which I have precious little these days!)


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## goldsilverpro (Jun 13, 2015)

4metals said:


> As a system for decorative electroplating I agree with Chris but what about as a copper plating bath for making pure copper from anodes with low concentrations of PM's?
> 
> A lot of things will influence its benefit as a copper refining cell. First will be the actual rate it can deposit pure copper at the cathode, second will be wether impurities in the anode carry over to the cathode rather than reporting to the anode slimes, and finally how low the metals remaining in solution when you switch to a dummy anode to remove can actually go. ( for it to be truly non hazardous, the only true value of the idea, it will have to completely strip the solution of metals).
> 
> May be worth playing with in my spare time ( of which I have precious little these days!)


I guess I was looking at it strictly from a plating viewpoint and, from there, I still feel that the concept of starting with no metal ion concentration is worthless. If the solution were first built up with copper (probably copper oxalate or some form of copper phosphate), it then might or might not be a functional plating bath. Experimentation.

You saw it as a potential electrolyte for electrorefining and the subsequent recovery of PMs in the slimes. It might very well work for this but we'll never know without experimentation. We've never really found a good electrolyte for the electrorefining of copper bars loaded with impurities. Maybe this is it.

Awhile back, I ran across lots of old info (mainly Google books) on the electrolytic separation of Cu and Zn in brass. I keep planning on looking at this more seriously.


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## rolynd (Jun 13, 2015)

Yes, with no metals in solution initially ,deposition will be slow and can progress only as fast as the dissolution of the anode. But apparently there IS deposition at the kathode , so albeit while slow, it works at least for copper as the vid shows. The patent also states that you apparently can add metal salts if you whish to do so. But this would negate the simplicicity of just using a metal of choice for anode whthout having to make or buy the metal salts. Plating electrolytes are usually not so easy to make , require proprietary additives and have to be maintained at certain concentrations etc etc. 

I felt tempted to play with it to see if I can get it to make a nice decorative silver plating. My concerns were rather about accidentally making some rather unwanted silver-ammonium compounds . But even if there were it wont be a problem if you dont evaporate until dry i think.
I dont mind if I have to leave it a few hours to get a nice coat. If the quality of the coat is at least as good as the cyanidefree silverplating electrolytes it would be a far cheaper and easier to maintain method. If it works for gold also - all the better. 

Since it can be used for so many different metals I dont think it will act selectively on alloys but since no one has played with it who can say?

You are probably right that it will not work as stated but It piqued my curiosity. If it works thats fine , if not I will have squandered some time on a useless effort. :roll: The needed chemicals are easy to get and cheap so not much loss in this regard...


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## janbbeck (Jun 15, 2016)

I have played with that solution quite a bit. The copper plating is slow at first, but the solution darkens over time and the copper starts depositing faster. I am having real trouble with depositing stainless steel, though.
I put up my adventures as a 5 part series here 

https://sites.google.com/site/janbeck/safer-electroplating-1

I don't understand the electro-chemistry behind this very well at all, but I think a lot of people here do. Any suggestions? Anything you would like me to try for curiosities sake?


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## Lou (Jun 15, 2016)

Copper oxalate is not well soluble. I'd guess sulfamic acid would be better.


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## janbbeck (Jun 15, 2016)

I guess that explains a lot of crud building up on the copper anode?


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## janbbeck (Jun 28, 2016)

Sulfamic acid was a great suggestion! I did some experiments and it looks like the solution basically acts the same, minus the crud building up on the anodes:

https://sites.google.com/site/janbeck/safer-electroplating-solution-6


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## janbbeck (Jun 28, 2016)

goldsilverpro said:


> rolynd said:
> 
> 
> > Stumbled upon this patent lately http://www.google.com/patents/US20050230264
> ...



I just ran an experiment again and the solution is very good at making very thick deposits of copper. I have not had much success with other metals, but the speed at which it deposits copper is just about good enough for electro-forming...

Just though you might find that interesting.


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## rolynd (Jul 2, 2016)

Thanks for your experiments Jan, you are quite persistent despite some faliures- I like that.
So the patent does not work for all the metals it claims. The only thing it really does good seems to be copper directly on steel which is not doable with a simple acidic copper electrolyte. (can be done with a basic coper electrolyte though)
There seems to be something missing. Usually plating solutions do have a variety of other stuff added to like levelers and brighteners to enhance the deposit.
For example Zinc plating from an acid chloride electrolyte will not or only barely work if no organic compounds are added. Now adays these additives are specialy fomulated levelers/brighteners which are not avaliable to the general public and are mostly proprietary. But if yo look a bit back in time often much simpler additives were used. This can be as simple as adding some sugar to the zinc plating solution.
Something that I found mentioned in a variety of plating solutions is triethanolamine, its mentioned for zinc, copper ,nickel silver and some other plating solutions. Its fairly easy to get since its not toxix and is used for example as leather softening agent, in dish washing soap, hand cleaners etc. The amount added varies from formula to formula but 10g/L should be an average starting point. Some have as low as 4g/l up to 30-35g/l


Some time ago I did some copper plating/electroforming experiments and the addition of 8-10g/l of TEA, 0,1-0,2 of sacharin, and a bit of an nonionic surfactant (tween 20) to a simple acidic copper electrolyte did greatly enhance the quality of the deposit I was able to achieve esp on thicker deposits. 

Another thing the industry does with notoriously hard to plate metals is pulse plating. Instead of a constant current/voltage a pulse generator is added and the plating is done at frequencies between 200-2000Hz to give a general range. The pulse can be as simple as an on/off rectangulat waveform up to more complex waveforms like pulse/pulse reverse or pulse superimposed over basic pulse. What this does is it enhances the adherence to the substrate by multiplying the grain nucleation sites and it hinders dendritic growth making for a denser more fine grained and smooth/bright deposit. Since I am not an electronic wiz I never did play around with the pulse plating idea. 

You seem to like experimenting with this solution so if you like try some additives - maybe it will enhance the deposit for the metals where it wont work properly now.


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## janbbeck (Jul 2, 2016)

Thanks for all that information!

What I am trying to figure out at the moment is the purpose for the 3 ingredients. For example, in nickel plating baths, it appears that boric acid is added as a buffer. And saccharin as brightener/leveler. So their purpose is clear.

Do you have any guess what the purpose for the individual ingredients is here? Can either of the 3 act as a buffer? I am tempted to try plating just with the sulfamic acid to see if the others are just placebos...


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## rolynd (Jul 3, 2016)

The oxalic/sulfamic is the obvious complex bildner, the ammonium sulfate may be added to increase conductivity and the tsp brings down the ph and adds to overall conductivity as well. without the tsp the solution will be much more acidic. but tsp is also able of complexing 2+ and 3+ metal ions so the roles of the ingredients are not as clear cut as in "traditional" plating baths. some plating baths will work only within a specific range of ph value so without the tsp it can still work but can also be a fail for some metals. Also some plating baths will make a proper deposit only within a fairly narrow current density range. E.G between 0,5 and 1,5 A/dm² (just as a sample) and fail to deposit or produce defective deposit below or above that range

If you seriously want to experiment with different formulas look into making (cheaper, just glue one up from acrylic or lucite, use usual dimensions)or purchasing a so called "Hull-cell" The Hull cell is a special shaped and dimensioned trapezoidal container that holds 267 ml of solution. This is what is used to test and experiment with new plating formulas. This shape allows one to place the test panel on an angle to the anode. As a result, the deposit is plated at different current densities which can then simply be measured with a hull cell ruler. This will let you observe the effects of different formulas ,additives and current densities on the quality of the plating much better than plating random objects. 
A new solution may work but just at a specific current density and if your plating object is outside of this you may consider it a fail whereas in fact its a working solution(if only for a narrower range of CD). You may happen upon a sweet spot in random testing but it will be hard to replicate if using different sized objects then.

The industry always strives towards high throwing power and wide current range because it makes plating operations much easier to control. 
developing your own working plating solution will be no mean feat and will take up a good amount of involved time and numerous faliures as well. But you seem to be persistent in your determination and not easily discouraged by faliures. So if you go on I would take his to a more controlled and repeatable R+D level. 
http://www.pfonline.com/articles/the-hull-cell-key-to-better-electroplating-part-i
http://www.pfonline.com/articles/the-hull-cell-key-to-better-electroplating-part-ii
Just my 2 cents...

you also tried plating aluminium - without success, which is no surprise. Aluminium, due to the native forming passive oxide layer is not receptible for plating. It usually has to be pre-treated in a electroless zincate solution(immersion plating, no current). Once a zincate layer is formed it can be plated with other metals on top of this. Here is a variety of formulas for zincate electrolyte: http://www.finishing.com/424/16.shtml

I definitively wish you luck in your endeavour , its certainly an intriguing concept so : Happy plating! And please share the results with us- I dont have the time and drive to do this myself but follow your experiments with interest! I commented in the video from mr murray smith some time ago to share some of the above but for some reason he deleted my comment? Your mentioning of this forum there brought me back here.


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## janbbeck (Jul 7, 2016)

Thanks for all that information!

The hull cell seems like an obvious thing to do now that I see it. My original thinking was to separate the electrodes as far as possible to get a more uniform plating. But of course the hull cell is better to experiment with.

Will update as I find out more.


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## janbbeck (Aug 7, 2016)

Still haven't gotten around to doing this. Working on making hull cell...

But I have a question. I did notice in my experiments that the result right below/at the surface of the plating bath is often vastly different from the rest of the sample. Does anyone have an explanation?

In the past, I did aerate such a bath to see if it was due to oxygen exposure, but that made no difference.


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## 4metals (Aug 7, 2016)

I haven't run a Hull cell in 35 plus years but back then, I ran them quite often. I think the top edge demarcating the solution level in the hull cell is due to the air / solution interface and the fact that ripples in the solution cause that interface to be intermittently in and out of the electrolyte during the test, causing the different appearance of the deposit. 

Similarly, if you ever electroplated parts hung on copper wire, the section of the wire where the wire entered the solution looked much different, usually duller due to the surface finish. This was for the same reason you are seeing on your hull cell panels.


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## janbbeck (Aug 7, 2016)

Thanks for the quick answer. The reason I asked was that in some experiments it looked like that was the only area I got a decent deposit at all. So I wanted to know what I can learn from that to improve the process. Since aeration and agitation did not make a difference, I don't understand what else could be different in that region.

One more question. When I used the solution to try and plate from a pure chromium anode, the solution was first tinged orange right next to the anode, and as that was drawn towards the cathode it turned blueish purple. 

So I had an orange area next to the cathode and then an increasingly dark remainder of the plating solution.

Based on your experience, can you draw any information about what is happening there? Is is clear that the chromium goes into solution somehow, but it will not deposit on the cathode...


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## NobleMetalsRecovery (Oct 3, 2016)

Hi Jan,

Any updates? I've ordered the chemicals to give this a try.

Thanks for the warning about the TSP. I got the wrong kind also, but will order some pure TSP.

Regards, Steve


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