Sodium Sulphate increase in Nickel Plating Solution

A. I am not sure what you are asking; if you saying there is a build-up of sodium sulphate in your nickel bath someone, or your cleaning process must be adding it. However, if you are saying there is a build up of sodium and sulphate ions, then it is a different problem. How do you know it is sodium sulphate that is building up and not a mixture of additives that contain sodium and sulphate? Sodium sulphate is ionic and will exist in solution as sodium and sulphate ions. These can come from many sources, including any additives you may put into your (currently unspecified) bath. For instance, if you are adding nickel sulphate and sodium lauryl sulphate as a wetting agent to the bath, you will be adding sodium and sulphate and this will result in an increase in sodium and sulphate ions, but this does not really mean there is an increase in sodium sulphate. You must give more details of your process so the chemistry can be understood. One thought - if you are using a nickel sulphate bath, are you using an active or inert anode? If it is active, are you getting an increase in nickel too?

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2002

A. sulphate will increase in a nickel plating solution if there are not enough anodes and anode area. The anodes will polarize causing nickel to plate out of the nickel sulphate leaving sulphates behind. The deposits will tend to become brittle due to oxidation at the anodes. Recommendation add more anodes of the proper type.

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])
2002


2002

A. Mr. Ishtiaq Hussain Siddiqui,

I presume you have had your Nickel solution tested at a reliable lab and are certain of your findings that Sod sulphate is actually building up. What is the figure in grams per liter you have with you for Sod sulphate content?

Is the increase in both the SB and Bright bath ?

Sodium sulphate precipitates when temperatures fall depending on the content in GPL.

Sod sulphate could increase due to the following

1) Water supply. If you use ground water to make up dragout losses, if your last rinse before Nickel is ground water. Have you tested the water for TDS and what was the total sulphate content. ? Beneficial to use deionized , distilled water in the last rinse preceding Nickel,, and in dragouts. Install a DI water plant .

2) What type of salts do you consume. Is it straight Nickel sulphate and Nickel Chloride ? Or do you add a compounded ready to use Nickel salt ? Sometimes these compounded salts can contain sod sulphate.

3) How much anode is present in the bath per litre of solution?

A good number is 85 to 100 grams of NICKEL ANODE per litre of solution. This keeps anode CD down , good for dissolution, and cuts down need for too much Nickel sulphate consumption . What pH do you run the SB and Bright bath ? Do you use sulfuric acid to adjust pH.

A good pH for the SB is 4 - 4.2. ph : For the bright bath is best to follow supplier data sheet. ( Wide range 4.2 to to 4.8 ) Use HCl in the Bright bath only, once a week to help anode corrosion. Do not use HCl in the SB bath to adjust pH, stay with Sulfuric.

Who controls the baths ? Is regular analysis done ? By you or by an outside agency ? or supplier ?

Regards,

Asif Nurie [deceased]
- New Delhi, India
With deep regret we sadly advise that Asif passed away on Jan 24, 2016

A. Just add some pure nickel in granular form and perchloric acid. I don't know the concentration of your solution so do it on lab scale and then calculate for the rest solution. Thanks and regards

Saleem Khan Afridi
inorganic chemist - Karachi, Pakistan
June 22, 2013