Sciencemadness Discussion Board

preventing a smooth silver coating

phlogiston - 20-8-2012 at 23:20

I have a solution containing silver that I got from dissolving old X-ray film in a mixture of bleach and sodium hydroxide. To reduce the silver, I suspended a copper sheet in the solution.
The sheet quickly gets covered with a beautifully smooth layer of silver. However, it apparently completely covers the copper since the reaction then stops.

I know there are agents that can be added to electroplating baths that help to obtain a smooth coating (urea for instance). Does anyone know compounds that are known to do the opposite, i.e. interfere with forming a smooth coating?

[Edited on 21-8-2012 by phlogiston]

weiming1998 - 21-8-2012 at 04:03

Quote: Originally posted by phlogiston  
I have a solution containing silver that I got from dissolving old X-ray film in a mixture of bleach and sodium hydroxide. To reduce the silver, I suspended a copper sheet in the solution.
The sheet quickly gets covered with a beautifully smooth layer of silver. However, it apparently completely covers the copper since the reaction then stops.

I know there are agents that can be added to electroplating baths that help to obtain a smooth coating (urea for instance). Does anyone know compounds that are known to do the opposite, i.e. interfere with forming a smooth coating?

[Edited on 21-8-2012 by phlogiston]


Instead of sticking copper in, reduce the Ag+ ions with a mixture of sugar and NaOH. I obtained almost pure silver powder from reducing AgCl with it.

blogfast25 - 21-8-2012 at 05:02

Quote: Originally posted by weiming1998  

[Edited on 21-8-2012 by phlogiston][/rquote]

Instead of sticking copper in, reduce the Ag+ ions with a mixture of sugar and NaOH. I obtained almost pure silver powder from reducing AgCl with it.


It's quicker with glycose syrup and even better is sodium fomate, acc. Fleaker.