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Copper is peeling off of Wood's Nickel strike
Q. I'm an electroplating engineer.
My English is not good, but I'll try to show my question correctly.
I plated acid copper coat (about 1.5 mm) on a Cr-Mo-Fe alloy roller.
First, we did nickel plating on the roller with a wood's nickel strike, then rinsed with tap water.
Then copper plated (CuSO4 bath) on wood's nickel layer.
We have some problems; the adhesion is not good between Ni and Cu. Or sometimes there is peeling between bottom layer Cu and middle-layer Cu.
Can anyone give me suggestions of how to solve this problem? Thanks a lot.
plating shop employee - Taiwan
November 10, 2010
A. You left the nickel anodes in the tank when not ion use, the metal increased, the inefficient "strike" then became an "efficient plating solution", you lost adhesion. Start over and keep the metal down. Bob Probert
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina
November 12, 2010
Q. thanks for your suggestion.
we always left the nickel anodes in the tank when not in use.
We have two Wood's nickel tanks and the conc. of nickel ion are 80 and 65 g/L,respectively.
Is nickel ion conc. too high?
thanks
- Taiwan
November 17, 2010
A. Yes, you have two highly efficient nickel plating solutions. Cut at least in half, preferably down to 1/4, add back Hydrochloric Acid, and you will have adhesion, then keep the anodes out when not in use. S-round nickel button dissolve too fast, and raise the metal too fast. Use Rolled Depolarized and bagged, nickel anodes. You can "dummy" with bagged carbon anodes to plate out the nickel but deadly chlorine gas is released. Preferably, cut the bath, then when you titrate the metal climbing, then use bagged carbon anodes WITH PLENTY OF VENTILATION TO PLATE THE METAL BACK DOWN.
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina
November 17, 2010
A. You say Cr- Mo-Fe parent material. If this is the 41xx series, why the Woods Ni strike. I think that a copper strike - high cyanide- would be more appropriate.
There is a possibility that you are not getting from the strike tank to the copper tank quick enough and the Ni is passivating. You say that it sometimes happens between two of the copper layers which has a high probability of the first Cu layer passivating.
- Navarre, Florida
November 18, 2010
A. I agree with Jim, try cyanide copper instead of nickel strike and acid copper
Sara Michaeli
Tel-Aviv-Yafo, Israel
November 21, 2010
November 23, 2010
Q. Thanks in advance for your help.
The parent material is SCM440 SCM4.
The chemical composition shown in the table below.
C 0.39 %
Si 0.32 %
Mn 0.71 %
P 0.014 %
S 0.011 %
Cr 0.99 %
Mo 0.24 %
Cyanide is very dangerous so my boss forbid me to use it.
Can I use Wood's nickel?
Thanks a lot.
- Taiwan
A. Yes, you can use a Woods strike. I am on the road without books, so I can not comment on Bob's dilution comments. For Stainless steel, we are normally in close agreement.
This is not a stainless and the Mo percentage is high enough to require a more aggressive strike than a mid carbon steel would. I would leave it in the tank under power for about 1 - 2 min longer than it takes to get a uniform color. Work this out on a scrap part.
Go from the strike to the rinse to the copper tank with no delays or it will passivate. Keeping it wet during movement does help to delay the onset.
When your Woods strike tank starts to smell like rotten eggs, carbon treat it and probably cut the tank concentrations back to the starting point.
Should work.
- Navarre, Florida
November 23, 2010
Q. We add HCl into the wood's nickel bath when the bath pH greater then 0.5.
H ion can disperse on the cathode, but Cl ion can't disappear during the plating process.
If Cl ion accumulated in the bath, is it any influence on this process? How can I reduce the Cl ion concentration?
Thanks for your help!
- Taiwan, Taoyuan
February 21, 2013
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