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Tin/Cobalt plating bath that is converting Stannous to Stannate at a rapid rate

(-----) 2006

We have a Tin/Cobalt Plating bath that is converting Stannous to Stannate at a rapid rate. I read in a earlier posting of a "Plating Reactor" to help convert back to Stannous. Does anyone know about this or who to contact about this problem.

Beth Klingler
National Metalwares, L.P. - Aurora, Illinois, USA
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2006

What bath are you using? Stannous is normally reservered forthe Sn(II) cation whiltsst stannate is Sn (IV) as an anion - tin being amphoteric and all that.

However, the most common reason for tin being oxidised is because air is getting into the system - so don't use air agitation.

A better answer can be given if we have your operating details

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
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2006

Are you sure you don't mean that the tin is being oxidized to the stannic state? If this is what you are referring to then the most common answer is that some of this type of reaction is normal. If it is excessive it is generally due to air agitation or introducing air due to leaking seals in filter systems or finally too high an rpm for a barrel. If you are using a proprietary system (I presume) your vendor should advise you as to whether they have an additive which is compatible to the process you are utilizing which will reduce oxidation and/or a treatment additive to precipitate out the stannic tin.

Gene Packman
process supplier - Great Neck, New York
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