
Not a lecture hall but a roundtable with a seat for you!
60,000 topics spanning 36 years. Education, Aloha, & Fun
topic 56595
Excessive growth of foam in zinc plating bath (NH4Cl)
January 26, 2011
Q. Hello.
I need your help!
I Have a zinc plating process with (NH4Cl); all my concentration are in spec.
I have a problem with the finish of the metal because it is white (like a white cloud).
My passivation is with HNO3, but when I take out the piece from the bath I can observe the finish.
My tank has a lot of foam and I do not why?
(photo added Feb. 10)
What can I do to fix it?
Aracely RodriguezProduction manager - Mexico, Mty,N.L.
January 27, 2011
A. Hi,
The foam may be due to the surfactants & solubiliser used in carrier and brightener, you can ask the supplier to provide you with assistance by changing the additives to an non foaming brighteners, I guess you have a rack zinc plating with air agitation.
Regards
Praveen

Praveen Kumar
plating process supplier
Mumbai, India
January 27, 2011
Q. A lot of Thanks.
Do you know how I can control it while I develop another supplier?
My supplier said that their products are non-foam formulation and said that foam is from the pickle but the pickle tank does not have foam.
regards
- Monterrey, Nuevo Leon, Mexico
February 9, 2011
A. I am not sure that the foam is coming from the pickle, yet the fact that you do not observe a foam layer on the pickle, is not an argument. The foaming effect is observed in the electrolytic bath like the zinc plating and not in a dipping bath like a pickle.

Sara Michaeli

chemical process supplier
Tel-Aviv, Israel
![]() |
February 17, 2011
A. 1)I took the information as an ammonium chloride acid zinc bath and an electroplating bath. - Bucaramanga Santander Colombia February 18, 2011 A. Hi, ![]() Praveen Kumar plating process supplier Mumbai, India |
A. If the problem is a hole in a pipe the air also affects the appearance (I'm not sure why is it) maybe brightener oxidation.
Daniel Hernandez- Bucaramanga Santander Colombia
February 22, 2011
A. Hi,
You can find the non foaming brightener and additives in market to resolve your problem.

Praveen Kumar
plating process supplier
Mumbai, India
March 1, 2011
A. Dear Brother,
I was using Mixed chloride Bath, that is KCl + NH4Cl.
I sometimes encountered the same foam. I was using Chemistry of Columbia Chemicals and Growell.
There are two additives 1) Brightener 2) Wetter.
If the Wetter is less in bath there will be excess foam.
You may also be facing patches on deposit. Please check in Hull Cell. Wetter requirement will be around 5-10 ml/ltr.
Thanks & Regards,
Parashar S R
- PUNE, Maharashtra, India
March 5, 2011
Q. A lot of thanks.
Do you know How I can check (analytically) the concentration of the Wetter?
- Monterrey N.L., Mexico
Surfactant for Acid/Zinc Bath
June 23, 2020Q. Has anyone seen a reference regarding Sulfamic Acid as a wetting agent in Acid-Zinc baths? I've found one where Sulfamic Acid replaces Tergitol.
Ed Spencer- Wichita, Kansas, USA
----
Ed. note: Hi Ed. Hobbyists/amateurs are 100% welcome to try to develop any process they wish. You have previously introduced yourself, so we know who you are so are not concerned about where you got this reference. But can any responders please tell us where they find the information you offer? There is a lot of proprietary trade-secret knowledge involved in acid zinc processes, and a "no registration required" semi-anonymous website like this one has to work hard to make sure the things we crowd-source are indeed generic information, not things that we shouldn't -- for example, information from competitors or former employees :-)
