
plating, anodizing, & finishing Q&As since 1989
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Stannate ion in tin plating bath
May 11, 2010
I know there are a lot of factor with accelerate the stannate ion (Sn4+) forming, can anyone please let me know that the temperature bath temperature (50 °C) is one of the main factors for this problem? Thanks.
Alan Loosaisemiconductors - California
May 19, 2010
Alan,
As you probably already know, gradual oxidation of stannous ions to stannic ions is normal in acid tin plating. Atmospheric oxygen and subsequent hydrolysis forms insoluble metastannic acid. I have seen filter systems that were taking in air play havoc with tin baths. Why is your bath temp so high (50 degrees C)? Anyway, there is an antioxidant available for the bath through your supplier that will curb the formation of Sn(4). I can tell you that high temperature does play a role in your problem, but not sure if it is the #1 culprit.
process engineer - Malone, New York
June 3, 2010
Dear Alan,
Would you please tell me whether you are using Alkaline stannate bath? as I am not clear on your question.
- Bangalore, Karnataka, India
