Plating Copper onto Titanium

A. Hi Patrik,

The first thing you have a very bad adhesion for the copper to titanium, is difficult to plate on titanium. I have some different pretreatments method to do this activation. When the current decrease is the same as your anodes is passive no current will go through the anodes. I think you can see a black film on your anodes. About your pretreatment you must explain more about how you did your pretreatment step before the copper plating. To get a more brighter copper deposit you can try this method. 50 gr/l Copper sulphate, 180 gr/l kalium natrium tartrat (Rochelle salt), 50 gr/l Sodium hydroxide.

Regards,

A. Patrick,

Are you following the strict steps of activation in 3:1 HNO3-HF to red fuming and the dichromate? Are you controlling the HF content closely?. Your acid copper doesn't seem to be the problem. Please give us more info to better help.

Regards,

Thank you very much for your advise.

As pretreatment I've been using this cleaning process for both titanium cathode and copper anode:

1. Thorough washing in detergent solution
2. NaOH 10%
3. H2SO4/HCl 10%
Rinsing after each step.

After your replies I've also been trying the activation process with 1:3 HNO3:HF solution. There was a reaction taking place with gas formation (green). It was obvious that the solution etches the outer layer of the titanium electrode, it was smaller afterwards. Is the purpose to remove a TiO2 layer?

Unfortunately the plating wasn't much more successful afterwards. I still get the very porous dark copper that falls apart. It seems like there is a thin bright copper layer right next to the cathode, but when running the process for a longer time it is also converted into this porous material. Two times I've succeeded getting a thin bright deposit, but only when running the plating for a short while.

I have the option of depositing another metal layer on top of the electrode and now I'm thinking of what metal to use. Platinum or palladium should be good I guess, I want it to be a good copper seed material and at the same time very inert in the electrolyte. Another option may be to make the whole electrode in stainless steel. What materials are the best when it comes to copper seed properties?

One last question, what current density range should be used for a bright solid deposit according to you?

Best regards,

A. Hi Patrik. Although almost any plateable metal can be plated onto almost any plateable substrate, as a general rule it is probably best to plate more active metals onto more noble metals because you don't want the second metal to plate out spontaneously onto the first like copper sulphate ⇦ this on eBay or Amazon [affil links] spontaneously plates out on an iron nail ... that will introduce still more adhesion issues :-)

You are certainly welcome to try to plate any metal onto titanium that you wish, whether you are a beginner or an expert with decades of broad experience. But if you are a relative beginner, please plate some steel with a Wood's nickel strike, then do the copper strike and copper plating that James Watts suggested. After you have succeeded in getting good copper plating onto this very easy substrate, then it may be time to come back and look at titanium again. The issue is simply that plating onto titanium is very difficult under the best of circumstances, and if you have little experience to guide you, it becomes impractical to try to decide what adjustments to make because there are so many interactive variables that you'll chase your tail. But good luck!

Regards,

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A. Hi, Sue. It is hard to plate onto titanium. You might review ASM Metals Handbook, Vol. 5, "Surface Engineering", which has a good chapter on plating of titanium and refractory metals. This should give you some hints as to whether the requirements for plating onto titanium would conflict with your other requirements. Good luck.

Regards,

A. Hi,
The pretreatment steps (activating) for plating on titanium is to pretreat both alpha and beta phase with different activating steps in the titanium, so I don't think your needing to protect Alpha will help you when you copper plate on titanium.

I have an easy way to plate on titanium here which doesn't etch titanium too hard and is nice both to Alpha and the beta phase.

Method 1:

Method 2:

I will also recommend you to read the following from the literature and try to understand the problem with it.

Regards,

A. First, I would want to make sure that Ti and Cu do not form an intermetallic alloy at that temperature and pressure.

Years ago we had 4340 alloy copper plated to prevent decarburizarion of the surface during a heat treat cycle. It did not work very well and required thicker and thicker coats.
We eventually went to salt bath hardening which worked great.
So, even if you get copper to stick, There is no guarantee that you will not get alpha case. We got it several times welding in a bubble that had not been vacuum purged with an argon flow three times.

So, you have a challenging problem.

A. Superplastic forming(SPF)

"Superplastic alloys can be stretched at higher temperatures by several times of their initial length without breaking."

The only pure metal, ductile enough to meet this extreme condition is pure gold.

The only satisfactory adhesion I was able to deposit on a highly polish(mirror bright) pure titanium surface was by Physical Vapor Deposition(magnetron sputtering).The coating was a multilayer of titanium, titanium carbonitride, gold at several microns thick.

I'd check the internet for SPF titanium alloy compositions:, the types available: alpha, alpha + beta, beta.

Good luck,