Nickel carbonate: How to increase pH in nickel plating bath

A. Best of luck to you! I believe that in some countries nickel carbonate is now classified as a category 1 carcinogen. That means it is very carcinogenic to man and should be avoided unless there is no alternative. Nickel carbonate was used as a means of increasing the pH in nickel plating baths where the bath suffered metal depletion as well as pH decreases. The carbonate neutralised the acid and the nickel content boosted the metal ion levels.

A. Nickel carbonate is a good way to bring up the pH of your bath. When the carbonate dissolves, the carbonate ion forms water and carbon dioxide that leaves your solution as a gas. This leaves no unwanted ions in your bath. Dilution with DI water will raise the pH eventually, but it takes a lot of water because of the buffering effects of all the ions in solution, especially boric acid. By adding 20% DI you have diluted your solution by 20%. This means that if your bath was at 80 g/l nickel, it is now at 64 g/l. The same goes for other ions in the bath like chloride, boric acid etc. Now you will have to add nickel salts to bring your bath back up to the normal range. Hope this helps you. Cheers, Don Piett - Thompson, Manitoba, Canada A. Nickel Carbonate dissolves very very slowly, so what happened in your case was that at first nothing happened, but by the time you added water it had time to dissolve. Next time add the Nickel Carbonate thru a filter. If small make a slurry in a bucket and pump in thru a filter. If you have a slurry tank filter then add it thru the slurry tank. Better still, why does your pH go down? Apparently your anodes are polarizing from too little halogen and/or too high anode current density and/or you are using insoluble anodes. Correct the anode problems and try not to have to use Nickel Carbonate (most of the commercial product is loaded with lead and other impurities). Robert H Probert Robert H Probert Technical Services Garner, North Carolina A. pH control of nickel baths has been well covered in recent submissions. Look at 18923 and 18637 for starters; there are also numerous other ones on this site. Trevor Crichton R&D practical scientist Chesham, Bucks, UK

A. Yanlu,

It is not a good idea to add water for you are diluting your bath. You have to continue with NiCO3 and give it time to react. If you see outgassing carbonate is working. Increase temp, agitate, filter and dummy. pH will go up. But above all, why is your pH low? It should remain or go up in a properly operated bath. You may have an unbalance of anode to cathode area or poor anode dissolution.

Check this first, Bye.

A. Dear Mr.Zhai,

The best chemical you can use to increase the pH in Nickel Bath is Lithium Carbonate it is relatively inexpensive and sure does the job with a minimum sludge. Just make sure not to use continuously since it will decrease the Ni content in your bath. Last but not Least, find out about the anodes in your bath... contacts.... partially filled baskets... drag in of acids... low chloride content causing low anode corrosion etc.

A. Control the galvanico bath daily and you make the additions precise. by own experiences, pH I raise it with just a little bit of NaOH.

A. Dear Sir:

The nickel carbonate should be good for most pH raising applications. Quite some time ago, a company (possibly M&T), sold a product known as "Instant Nickel Carbonate." This material allowed us to get the pH a few tenths of a pH unit higher than conventional Nickel Carbonate. It was important to us at the time, when performing high pH treatments to Nickel Plating Baths.

You may wish to check with your vendors to see if this product is still marketed.