recommed me a leveling agent for copper plating

[coppercone2]

I got my SPS brightening agent
I got my PEG supressor


I still need a leveler.

Does anyone have any suggestions, so I can happily fabricate thick copper structures with electricity?


I got janus green B because its the standard. I would love to hear from someone that has experimented with this to try to make commercial quality plating.

[T3sl4co1l]

Just thiourea worked fine for me, when I was playing with it. I forget what all I used but it wasn't very picky for generic use. Tap water, copper sulfate of modest strength, a bit of acid, chloride, and a few drops of Tarn-X (thiourea and a detergent, I think).

That did things like, a dense matte (crystals evident) deposit, on graphite electrodes, thick enough (a few days at low to modest current?) to get a good connection and last a while in a corrosive environment.

Never had any of the other modifiers on hand, but in the right amounts (these are very minor things, a little will do, don't overdo it, it's like semi doping) that should do very well, fine grained smooth or even shiny deposit.  At that point, you might need to pay attention to minor impurities: sulfate, calcium, alkali, transition metals; organics...

Probably, those modifiers are more important for other metals; copper is one of the easier things to plate, I never succeeded with anything else (but again, didn't try very hard).

Tim

[coppercone2]

I was hoping to try some hard things like maybe trying to do a electroplating weld

I don't know if thiourea is a leveler, brightener or suppressor

the terms seem to be contested

Since its sulfur bearing, I think Thiourea is a brightener.

The levelers are usually dyes or some kind of ammonia thing, which urea is.

they say levelers are either some quantary amine or a dye. I went with dye since it seems to be referenced everywhere


I see they say it can be used for either purpose, of course that is totally confusing, that sounds like the substitute teacher


They seem to make a stink about dyes, and how non dye could be better, but I did not see thiourea listed there, even though its liek 1000x more basic then what they suggest. Is there some grizzly industrial OSHA thing about thiourea ?

It seems that messing with levelers can lead to problems like levelers being absorbed in the copper.


and thiourea stinks 

[coppercone2]

so is thiourea a non dye leveler AND brightener? 

[coppercone2]

This project also came out more expensive, if you don't want to keep your chemicals in shitty bags. I got all the proper media bottles and stuff so I am confident about storage and thats a pretty big surcharge. I had some random chemicals in ziplock bags for ages and wow does it feel great to put them in proper chemistry containers.

[coppercone2]

well, it became very blue

and now I am blue because I bought a wide copper pipe for the anode. I read it should be phosphorus copper, meaning you need a copper plumbing pipe that has the 0.05% phosphorus.

I think the tank geometry that is good is 1/2 tank OD copper cylinder, with the part submerged in the middle bottom half of the tank (so for a 4 inch tall tank, 2 inch tall pipe and part suspended 1 inch off ground and  1 inch away from pipe in the middle

I used copper chloride anhydrous for my chloride ion, instead of messing with HCl. It was easier to use the powder then to try to dilute HCl.

The Janus Green B is very potent dye, for my 200mL sample, 6 miligrams made it absurdly blue.

[coppercone2]

my mixture worked well for about 3 hours but when I left it on over night the bottom of my coin got kinda looking like slag and 90% of the object turned hazy/frosted copper.. this is for the high throw bath for vias

Next time I try
1) agitation with mag stirrer
2) making part lower then electrode (electrode was just sittin in beaker with part in the middle), your not supposed to have the electrode lower then 1/2 of the part.

The

"IN G
TR "

part of the coin looks great though after 12 hours @ ~50mA/square inch

It looks like the scratched up screen of a sand blasting machine, but copper color.


it does however weigh about 9.5 grams, compared to a 5.6 gram quarter. Its copper clad to like 3-4 oz. It needs some work before it can handle useful current

[T3sl4co1l]

May want a reversal power supply as well.  Simply put the cell under an H-bridge and run it like that, at some modest duty cycle (say 80% ballpark).  Frequency lower than ionic cutoff / diffusion limit; fractional Hz probably.  I don't know what settings are best, and I'm sure there are electrolyte tweaks to go with, so, see what works.

Operating principle is, asperities are preferentially removed during negative, then plated uniformly while positive.

I don't know if additives are consumed or decomposed in solution, and need to be re-upped from time to time.  May be something to check.

I remember getting a nicely dense (if lumpy) deposit, running a cell for long term with just the thiourea in use.  Not something you could use for a board that thick, but I mean, it was well past "heavy copper" territory.  Lemme see.. I still have the largest plate I made back then,



mostly about 1/8" thick, with knobs out to maybe 1/2", mostly around the edges.  Behind, I *think* was the backing plate I grew it on, with various other deposits still stuck to it (with poorly-washed remnants of electrolyte giving the patina).  This was without reversal.

Never got around to melting it, before I moved... that stuff's been in storage forever

Had also built a reverser circuit around that time, but similarly didn't get a chance to use it.  Not that I had much reason to grow heavy copper on what few PCBs I made, nor had the activators to make PTH.

Tim

[coppercone2]

I can do duty cycle up to 2A on my linear amp with DC (HP) using a function generator. up to some KHz.

That looks gnarly. Mine is just a little rough but its only 4oz you have like a few pound copper there.

From what I understand
1) there is conductive sediment on the bottom of container that makes a parasitic electrode. Stirring negates it, filtration removes it. You can also do something with 'tea bags' but that part is just irritating me right now to think about making socks.

2) the OUP (object undergoing plating) should be hung with its mid point at the bottom of the electrode.

3) a circular electrode might be the best (which is why I got high diameter copper tube, I can TIG copper weld it into the perfect shape if I want to

4) my bath is very high throw (lots of H2SO4), for plating flat objects I think you want much less H2SO4. Mine was meant for vias. I would say it delivered, if it made 4oz plating. I just need to try it on a PCB

5) the balance should be 70% standard polarity or so square wave (soft square?) for optimum results on ... dc offset PWM. Not sure if you need a dead zone though (i.e. not simple PWM)

6) electroforming should be slow, 60mA/square inch or so. If you have filter and stirring it should get rid of the "my cell gets worse with time problems)

7) copper should be phosphorous copper type (0.03-0.06% phosphorous, rest copper. Apparantly plumbing tubing satisfies this condition)

electrode need scrubbing eventually because of fowling. I have a 4x stir plate  hot plate thing, I wanted to make a round robin thing with electrocleaning, cleanbath, etc. I suspect that the best way to clean this shit might be a citrate solution in ultrasonic cleaner, followed up by electropolishing. That should keep that electrode looking proper.

9) Cell is not efficent with copper, eventually the electrodes dissolve in it. Not sure how to determine this, the best I can figure it to burn and weigh a sample from volume. I.e. the idea is you remove 1/4 bath, and add H2SO4 and water, and additives in proportion, to dilute it to maintain your desired concentration. It is simple accounting for the copper, the dye... you can use a spectrophotometer and a cuvtette to control it... but the other additive (SPS and PEG) I don't know. I thought maybe you can track PEG using a viscosity tester. The SPS is a wild card however!!!! I don't know how to deal with that shit. a MS?? I imagine the best way might be to totally destroy/capture the additives some how (hydrogen peroxide? active carbon?) filter it, and add new additives by volume. You don't need alot.. it might not be absolutely necessary to conserve them). I bet someone knows about this.

**** or since its heavy, it might be possible to just weigh a 1mL volumetric flask on a precise scale to work out density! alot better then burning.


I don't know how far you can take those best practices anyway. At some point its going to lump and I assume what you need to do is take it out and sand it at some point, unless there is a trick, like periodic electropolishing after it gets a bit lump. It sounds like I would need a robot arm to move around between baths. I personally would like to find a solution that is minimum sanding, I notice that its smart to figure out ways to avoid abrasives, their a blunt instrument .. any cave life can rub something on a stone


 Interestingly I can play with anodizing dutty cycle on a kepco I have if I ever fix it (never plugged it in for 2 years), I think it was broken, for the HV.


I think that all these control measures would just extend the time before bumps appear, and I doubt that you can take it that far to deposit pristine bus bars in a single bath very easily.



The best information is IMO the 1970's NASA videos, because they make rocket engine coolers with this technique, which may be replaced by metal 3d printing, maybe or maybe not. They put some seriously thick copper on those rocket, but it required machining, they did not perfect the method, and they might never because 3d printer is easier to manage and gets public approval for being fancy. The body of the rocket is clad with heat exchange channels that the fuel goes through to cool the engine down to reasonable temperatures (i.e. 'the rocketeer').I personally think in the far future electro deposition techniques will be perfected because if you figure out how its very simple and you can setup a rocket thruster manufacturing facility on any old planet with some copper ore. no dependance on mom to get you lasers and shit

[T3sl4co1l]

Yeah, IIRC that deposit was pretty flat for a few days, until the growths started getting pronounced.  Might've been slow on re-upping the thiourea too and that's when the growths started, then smoothed out again, then etc., I don't know.

I put down probably 10 or 20 thou on the graphite electrodes I did, and it was fine, matte to visibly crystalline.

I didn't have stirring, which will be a big contributor to unevenness.  I also had a fairly dirty bath as I was using a crude (maybe 90, 95%?) melted bar for the anode.  There might've been too much chloride present, it would cake up with Cu2Cl2 a bit, unless that was PbSO4 or other impurities laying around.  I didn't analyze the anode sludge (I don't actually remember if I did any workup of it, or just filtered and trashed it..?!).

Anode doesn't matter, it's dissolving, just don't let it drop bits really, and maybe filter from time to time (or continuously with a pump, good for stirring action too) to handle any precipitate or sludge that forms (don't want anything getting trapped in the deposit, weakening it or introducing impurity).  As much copper is removed as deposited, unless you're using an inert anode (PbO2, Pt?) and Cu concentration is falling while the anode bubbles off O2 (or forms persulfate), or you're running entirely too much current density and bubbling H2 at the cathode (Cu concentration rising) (but obviously, you aren't going to be doing that *and* getting a good deposit, and with [Cu] rising, the problem sort of solves itself).

Tim

[coppercone2]

And spinning might help its like a antenna running over the maximum frequency when it gets dirty and develops lobes, I wonder if the lumps occur because there is area of the electrode that are dirty that force current path to change.

Performing the same experiment but changing the electrode to a fresh one after every 3 hours might provide very interesting results for thick plating ! There is no way to determine which parameter is causing problems unless you swap things out IMO. I can do this experiment with copper sheet because its bothering me, I never saw data that tells you what happen if you electrode is always clean........   ... just assumptions

[coppercone2]

In my test the electtrode was the entire beaker wall, and the part was in the middle (half circle electrode). The bottom of the coin is substantially thicker then the top, the last 1/8 inch of the quarter has like a wart on it. I don't know why that is. It makes me think the bottom of the beaker is doing something


I only made up 200ML of solution, next one will be on a nickel coin thats smaller then a quarter and I will cut the electrode in half so its not sitting on the bottom of the beaker


It is irritating because after 3 hours, it looked like perfect, I could sell that to someone.

[coppercone2]

It should be this



I imagine for 3d plating, you would want two pipes, one under and one over the OUP, with the pipes being 3-4 times the diameter of the object

they make it more fancy too



that is hard though

[coppercone2]

As much copper is removed as deposited, unless you're using an inert anode (PbO2, Pt?) and Cu concentration is falling while the anode bubbles off O2 (or forms persulfate), or you're running entirely too much current density and bubbling H2 at the cathode (Cu concentration rising) (but obviously, you aren't going to be doing that *and* getting a good deposit, and with [Cu] rising, the problem sort of solves itself).

People are saying this is not true, that in a normal bath your copper concentration goes up! not all gets put on work piece, it goes into solution, hence the idea that you need to dilute the mixture once in a while. I don't know exactly how much this is. It is said in the context of a properly functioning plating bath, it just seems to be a bath maintence reality... they define it as not being 100% efficient. This is in addition to filtering the sludge, that you actually have excess IONS in the solution some how, that you need to dilute out. Or I guess plate out some how, with a inert electrode (does this deplete the solution?)

I don't know WHY this is happening, but its what people are saying about the realities of copper plate solutions! If this is true I imagine it gives someone with a strong academic knowledge alot of problems!


THis is why I suggested density testing, to try to measure if there is more copper in the used solution after filtering. It should be easy to measure it.

I have a feeling that it might be true  because in general there is alot of things that happen outside of the "superconductive copper block on a zero friction ramp" approach to process design


A few percent should be easy to pick up on a scale. I did not measure density before, when I make up my 1L batch after more testing I will keep an eye on density. Only caviat is you need to make sure to take temperature into account.

[T3sl4co1l]

That doesn't happen... redox is redox, and copper is copper.

At least in a pure sulfate solution, Cu(I) isn't stable, the anode will only oxidize as Cu(II).

Now, it could be that sometimes the anode corrodes as Cu(I), e.g. as Cu2Cl2, because chloride is too high.  Perhaps this is even an intended feature of the bath (, I don't know.  If you aren't removing the Cu2Cl2 sludge (it's white, quickly turning greenish in air when moist), it can disproportionate to Cu(0) + Cu(II), or oxidize with air (particularly if a bubbler is used) to Cu(II) (which will also need to top up acid from time to time).

I do recall some gray or white sludge in those experiments, but I don't know if it was that, or lead or what.

Also if you aren't stirring, the solution becomes stratified, the Cu-heavy (literally denser) electrolyte falling off the anode and sinking to the bottom.  This, along with local depletion of ions near the cathode surface (and give or take further convection patterns)

Oh yeah, I also seem to remember striated deposits, don't remember if it was on that plate I showed or what.  But that could very well be due to cathode convection.

Insert Destin LAMINARFLOW gif here.

Tim

[coppercone2]

Well like I said its a method they recommend with trouble shooting, it would suggest the reaction is more complicated then we think, maybe there is a intermediate or something and it seems like common knowledge in electroplating troubleshooting related discussions.

I used CuCl2 as my chloride source, 24mg of anhydrous for ~200 grams of solution, it is easier then weighing and diluting acid

[IanB]

it is easier then weighing and diluting acid

I don't understand why you have mentioned acid more than once?

If you want to electroplate copper, you need copper ions, not chloride ions. Hydrochloric acid contains no copper ions, so it is on the surface, useless. (Pun intended.)

[coppercone2]

its chloride

[IanB]

Sorry, I meant to write copper. Brain fart. 

[coppercone2]

I don't see any need for sodium in there, I see that the chemistry knowledge is shady for this and it does not seem to work too good, sodium chloride made it in there because people have it in the kitchen probobly, I am not trying to make a soup

[T3sl4co1l]

Sodium shouldn't play any role, the ions are inert, and not concentrated enough to affect conductivity or whatever.  Chloride forms a complex with copper, though how exactly I don't know here; it's certainly not enough to turn the solution green (CuCl4(2-) ions) but is plenty to affect surface chemistry in some way.

Tim

[coppercone2]

maybe it gets high blood pressure