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Control of Ni electroplating bath with additive

2007

Hello.

These days, I test Ni electroplating bath with additives in barrel plating.
And the main chemical is saccharin and lauryl sulphate.

After a few days, I did carbon filtering to remove some impurity and additives for good plating. (The bath capacity of this test was about 5 liter.)

But when I tested in pilot line(about 400L), it seemed that the additive wasn't removed.
I think some impurity could be removed but not all of them. Because analysis of some additives is not easy, I want to add full amount of additives after all additive removed for additive concentration control.
Why carbon filtering didn't work?
And when you do carbon filtering how do you control additive concentration?

Also I want to use H2O2 for remove, I don't know the specific method.
I have no idea is this effective or its effects on plating quality if it remains in plating solution.
please let me know about method and cautions in H2O2 treatment.

Thank you.

Kim MiGum
chip plating - Korea

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There are more potent ways to remove organics, Kim, including adding H2O2 as you mention, and heating the solution to near boiling and mixing in carbon particles, then filtering after several hours. But most nickel plating is done with proprietary brightener systems rather than saccharin, and you can get advise on removing/controlling that particular brightener system from the supplier. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

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First of two simultaneous responses --

Peroxide treatments are not a cure all. They can easily make problems worse instead of better. People have the impression that hydrogen peroxide will oxidize organic contaminants all the way to CO2 and water, but this is seldom the case. Sometimes they leave partially oxidized contaminants in the bath that are difficult or impossible to remove.

Dave Wichern
Consultant - The Bronx, New York
2007

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Second of two simultaneous responses -- 2007

It is very difficult to remove saccharin from nickel solutions. hydrogen peroxide is not strong enough to remove very much.
a potassium permanganate [on eBay or Amazon] treatment is required. However, it is not usually necessary to remove saccharin unless you have made an addition that is too much to produce the hard deposit you seek. You will have a deposit that has compressive stress. If you are seeking brightness, a small amount of a secondary brightener will work in conjunction with saccharin.

Don Baudrand
Consultant - Poulsbo, Washington
(Don is co-author of "Plating on Plastics" [on Amazon or AbeBooks affil links]
           and "Plating ABS Plastics" [on Amazon or eBay or AbeBooks affil links])