Activation of old Nickel plating for new Electrolytic Nickel plating
A discussion started in 2002 but continuing through 2017(2002)
Q. I have few questions regarding the activation of Nickel surface prior to Nickel plating. (Nickel over nickel). The Nickel layer is not fresh it is coated using some other technique and sand blasted.
1. What is the best method for activation of Nickel surface prior to Electrolytic Nickel?
2. If electro-Activation is preferred which is the best? cathodic or anodic. Is there a possibility of contamination if cathodic is used?
3. Which cathodic method is advantageous (cyanide or acid)? What are the pros and cons (contamination / Hydrogen embrittlement - occlusion / etc etc)
4. What is the best anode material for cathodic activation? (cyanide Alkali / acid ) How to take care of the material dissolving into the solution? what is the expected life of the solution? How often should it be discarded?
5. What are the DSA (Dimensionally stable anode) that can be used? Do I have to use a membrane / anode cover if graphite or carbon anode is used?
I tried to search for the particular topic but very minimal information could be found in the site. please helpKarthik
A. Hello Karthik.
1. Sorry, I do not know the "best" method of activating nickel, but I do know that many nickel chrome platers who do products like bumpers generally include a nickel strike step these days; this allows them to mix alloy steel raw bumpers and previously plated bumpers together. So my answer is that a nickel strike step is an essential feature of activating old nickel.
2. Some platers use a Wood's nickel strike in "both directions"; they will start with the part anodic to help activate, and then switch to cathodic to apply the strike.
3. Robert Probert comments on cyanide activation in letter 38770. I can't comment on this further except to say that I don't think you should use cyanide if there is a viable alternative, and I think there is.
4.You use pure electrolytic nickel anodes in a Wood's nickel strike.
5. Sorry, I'm really not familiar with using DSA anodes in a nickel strike although they are widely used in precious metal plating.
Ted Mooney, P.E.
Pine Beach, New Jersey
There is no problem to activate nickel alloy or a nickel plated part.
1. Clean the part for 2 minutes anode/cathode cycle finish with anode.
3rd Generation in Plating
Consultant - Arvika, Sweden
A. In my experience, plating nickel on nickel is usually a tricky job. If you are doing a secondary build on top of a fresh first build, usually you can just let the work cool and plate it a second time - without any extra preparation. However, building on top of an older "in service" or "cured" build is different. I work mostly with steel as a base metal , so I use a normal steel to nickel preparation, then follow that with a cathodic acid etch ( usually 24% sulfuric ) and a nickel acid pre-plate. I have the same problem - most people really don't know. But I have done several repairs like this with approximately 95% rate of success.
I hope this helps!Dan Kahmann
- Kansas City , Missouri
Nickel over nickel , I think you have to follow the steps
1. soak cleaner
(#4 For the activation ,Need lead anodes)
March 30, 2011 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread
Q. Hi All
I am about to make up a Woods solution and wondered if Wood's Nickel Strike was okay to use as an activator to Re-Activate old plated nickel then plate Bright nickel on top ?
Can anybody advise me further?
Thanks to all.
polishing bike parts - London, United Kingdom
March 31, 2011
A. It will work most of the time and is the best strike for your purpose. You will find that some old oxidized and some polished nickel will take a lot stronger activation step.James Watts
- Navarre, Florida
October 19, 2011
I have seen three references in this thread to using lead counter electrode as a step in nickel activation, however in one case the work piece was anodic, and in two others it was cathodic. Is there a preferred direction here?
- Boston, Massachusetts
October 20, 2011
A. Hi, Stan.
Actually I don't think I would summarize the thread the same way:
A Wood's nickel strike, using nickel anodes and direct current (the workpiece being cathodic or negatively charged) is a necessary and fairly universal approach to activating nickel for plating upon it. Some users do apply reverse current for a period of time first.
But if the nickel is "old" or "not fresh", some readers suggested that the nickel strike should be proceeded by etching in acid with lead (or much more expensive DSA) cathodes. Mr. Patel said that the current for this should be "direct", but I think this may be a semantic error, and I agree with Mr. Sundman's posting that the workpiece should be anodic for this step. If possible, please review the "Adhesion" chapter in Jack Dini's "Electrodeposition: The Materials Science of Coatings and Substrates" as it offers quantitative data from testing some different approaches to Wood's Nickel activation.
Ted Mooney, P.E.
Pine Beach, New Jersey
Citric Acid for Nickel-on-Nickel Plating?March 16, 2017
Q. Recently I have been having troubles with plating a two-layer part, both layers being Nickel Sulfamate with some added cobalt. The first layer is a "plate down" - a pattern on a glass mandrel is replicated via electroforming. The part is then pattered with dry film photo resist, exposed and developed, and prepared for a second layer of nickel cobalt. Now you know Nickel does not plate very well on nickel, so before electroforming the second layer, an "activation" solution is used - made up of potassium iodide diluted with DI Water. The first layer nickel with photo resist sits in this solution for 30 minutes, then it is rinsed well with DI and placed into the tank to be electroformed. However, this solution almost always reveals a white-ish staining across the part.
Do you know of any other chemicals or solutions that are used to "activate" nickel for a second layer of nickel?
I appreciate any and all responses!
Process Engineering - Precision Electroformed Parts - Lowell, Massachusetts - USA
^- Privately contact this inquirer -^
A. Hi Ben. Have you tried a Wood's Nickel Strike or a Sulfamate Nickel Strike before the 2nd layer of Sulfamate Nickel?
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Striving to live "Aloha"
March 18, 2017
A. The cyanide or citric acid activation must be with current; the part is cathodic and it's only good for moderately oxidized nickel. Ted's advice of Nickel Chloride Strike is required for old tenacious heavily oxidized nickel.
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina
April 5, 2017
A. I suggest that you activate the first nickel electroform by immersing it in the nickel plating bath and then make the part anodic for 30 to 60 seconds and then make the part cathodic without removing it from the bath. As long as your nickel anodes are working properly, this activation process will work.
St Paul, Minnesota
April 7, 2017
A. The Iodine based formula for nickel over nickel activation contains potassium iodide, sulfuric acid and iodine. I have used it, and it works every bit as well as the Wood's nickel strike. Maybe even better.
I don't have a copy, but if you can find a copy of the Canning electroplating book, it is in there.
Jeffrey Holmes, CEF
April 11, 2017
A. Here is the iodine activation formula -
Add to one gallon of water the following chemicals:
3 Fluid ounces of concentrated sulfuric acid slowly with stirring.
One third ounce of Potassium Iodide.
0.002 Ounce = 0.062 Grams of solid Iodine.
The Potassium Iodide is dissolved in a separate small amount of water and the solid iodine is added. When the iodine has dissolved the solution is added to the cold diluted sulfuric acid solutions and thoroughly mixed. In use, the iodine should be added periodically to maintain a straw color.
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