Schildkröte
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Posts: 3
Registered: 31-8-2018
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Platinum anode problem
Hello, I tried electrolysis of impure zinc sulfate with little piece of platinum wire&sheet. The solution was originally transparent yet after few
hours of electrolysis the solution around the anode got pink, then purple. The platinum anode developed a thin film of red substance on surface which
started to fall of. Because I got scared that I will lose my platinum I took it out and put it in solution of sodium dithionite which immediately
returned the shiny surface of platinum back.
I'm not quite certain what happened, I guess the purple color was from manganese impurities which oxidized the surface? May the red substance be
chloroplatinic acid?
Anyone got an idea how to prevent the damage to electrode?
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zed
International Hazard
Posts: 2283
Registered: 6-9-2008
Location: Great State of Jefferson, City of Portland
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Mood: Semi-repentant Sith Lord
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Hmmm. Chloroplatinic acid can be formed by anodizing Platinum in concentrated HCl.
Platinum doesn't usually react with -SO4, but when anodized..... Maybe? Dunno!
I have done the trick, of anodizing items that are Chrome plated..... in Copper Sulfate solution, turning the Chromium Dull/Black..... Then reversing
the current, to plate out copper on the activated surface. Making it solder-able.
Sorry I can't be more helpful.
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Schildkröte
Harmless
Posts: 3
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Thank you for effort anyway! I will try to find another way out.
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Eianz
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Posts: 4
Registered: 9-9-2018
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Its due to electrolytic passivation
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