Schildkröte - 31-8-2018 at 11:15
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?
![IMG_20180703_151029_AO_HDR.jpg - 845kB](https://www.sciencemadness.org/whisper/files.php?pid=532555&aid=70280)
zed - 4-9-2018 at 15:41
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.
Schildkröte - 9-9-2018 at 13:07
Thank you for effort anyway! I will try to find another way out.
Eianz - 9-9-2018 at 22:51
Its due to electrolytic passivation