Metal finishing Q&As since 1989

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Effects of addition of sodium thiosulphate to bright nickel bath

I have accidentally added sodium thiosulphate [on eBay or Amazon] to my bright nickel bath. I want to know how to to remove it quickly without disturbing my production ?

K. Ramesh
- Mumbai, India
2005

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First of two simultaneous responses --

You have discovered that sodium thiosulphate makes your nickel plate very dull. By now you have probably also discovered that the effect does not last very long (depending on how much you added). If you added a small amount, say less than 1 gm/l, it will decompose harmlessly in a day or two. More will take longer. you can accelerate the process by dummying.

Jeffrey Holmes, CEF
Spartanburg, South Carolina
2005

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Second of two simultaneous responses --

You added some sodium thiosulphate in you bright nickel tank, how many gals did you added? Do you have roughness problem or loss the brightness problem ?
If you have roughness problem , dummy the nickel bath using lower amps and filter out nickel bath as much you can.After that run the hull cell panel and adjust your brightener .

Popatbhai B. Patel
electroplating consultant - Roseville, Michigan
2005

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2005

Hi,

Depending of the amount you have added it should not effect your production that bad. In fact, the Sodium can cause some problems, such like fast increasing of the pH (developing of rough deposits by falling out of hydroxide), higher hardness, brittleness, lower corrosion resistant etc. You still know how much sodium thiosulphate [on eBay or Amazon] you have added?

There is no way to get sodium out of the bath with the typical procedures (dummy plating). The only way I see (and again, depending on how much you have added)is to dilute your bath. In the history, I'm not quite sure some plating shops are still doing it, they have used thiosulphate to immune the bath against impurities caused by foreign metals.

Kind regards,

Dominik Michalek
- Mexico City, Mexico

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Again it is hard to advise when you don't say how much, but assuming it is a relatively small accidental addition then as it is a reducing agent I believe an equivalent amount of hydrogen peroxide would alleviate it,that is oxidise it to sulphate. I wouldn't worry about the sodium side of it as many brighteners are sodium salts and added every day.

Geoffrey Whitelaw
- Port Melbourne, Australia
2005