Where the
world gathers for metal finishing
Q&As since 1989


-----

Difficult to get the nickel sulfamate bath clear

September 10, 2008

I am making a batch of nickel sulfamate bath. However, I found it is hard to get the whole solution clear. There are always some light yellow color powders in the solution. The components of this bath is quite standard:


*Nickel Metal Content :11 oz/gal ( added as Nickel sulfamate)*

*Nickel Bromide content : 1.5 oz/gal (added as Nickel bromide)*

*Boric Acid content : 5.0 oz/gal (added as boric acid)*

I add all these together, then Di-water, and then start agitation. I didn't increase the temperature in the beginning. However, when I found the difficulty of dissolving, I heat the solution up to 40C. It didn't help at all.

I am wondering if there is a routine of adding the components, increasing temperature or other things need to pay attention to.

Zheng Liu
Student - New Jersey

---

It is interesting you are using nickel bromide - not the most common of nickel bath formulations! I wonder if the nickel bromide is pure of if it contains some insoluble impurities? Try dissolving just nickel bromide in water and see if you still get the insoluble "yellow powder".
I suppose the yellowness could also be due to the release of bromine, which will be a liquid at low temperatures, and this could be easily mistaken for a powder, especially if it is absorbed onto an insoluble species

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
September 15, 2008

---

I understand that bromide formulations have lower stress than the corresponding chloride ones. So I have read; I have no experience with them.

To the original poster: sounds like some kind of nickel oxide. I've seen insoluble solids like this in the past. Just filter it out, then do a Hull cell. If you get poor results, try an alternate source of chemicals.

Dave Wichern
Consultant - The Bronx, New York
September 22, 2008