video Make Silver Different Colors by Anodizing
How to Make Silver Different Colors by Electrochemical Anodizing.
Without using paint you can give a silver surface various colors by anodizing it.
WARNING: Anodizing solution is corrosive, so wear gloves at all times when working with it. It is also somewhat toxic, so keep it away from children and pets too.
To make the solution, just mix two tablespoons of sodium hydroxide (lye) and one tablespoon of sulfur with half a cup of water (~100mL). Stir for about ten minutes until the solution turns orange. Then filter the solution to remove excess sulfur.
You can get sulfur from online sources (including ebay) or from some drugstores. Sodium hydroxide is the primary component of some types of drain cleaners. But read the label carefuly, drain cleaners come in many types and alot of them don't have sodium hydroxide. You can also buy sodium hydroxide online, it's sold for making home biodiesel or homemade soap.
After you made your solution, thoroughly clean your silver article and place it into the solution. Attach the positive terminal of a 3V battery to the article and dip the negative wire into the solution. Move the negative wire around the solution to give the silver an even coat, or keep it in a single spot to apply rainbow effects.
What's happening is the electric current is oxidizing the silver and causing it to pick up the sulfur dissolved into the solution. As it does this it thickens and alters the way light reflects off the surface. What color of light is reflected is determined by how thick the sulfide layer is. The thickness of the layer is determined by how long you anodize it. So you can control the color by controlling the time you apply the current.
The process can be used to tint silver items to give them an antique look or simply just to make them exotic colors.
Practice before you do this on something valuable.
If you make a horrible mistake, you can restore the silver by electrochemistry at this link http://www.youtube.com/watch?v=vGCx9HZwYBo
Always use batteries for this process to keep safe. Also don't use higher voltage batteries, you might end up "burning" a layer of silver off your item and ruining delicate designs.
We've done it with copper, but the color is not as brilliant, silver gives the best effect for the video. We haven't tried it with steel and aluminum just goes dark without getting color.
Thanks for watching, subscribe, rate and comment!
If you like my videos, check out http://www.nurdrage.com
Without using paint you can give a silver surface various colors by anodizing it.
WARNING: Anodizing solution is corrosive, so wear gloves at all times when working with it. It is also somewhat toxic, so keep it away from children and pets too.
To make the solution, just mix two tablespoons of sodium hydroxide (lye) and one tablespoon of sulfur with half a cup of water (~100mL). Stir for about ten minutes until the solution turns orange. Then filter the solution to remove excess sulfur.
You can get sulfur from online sources (including ebay) or from some drugstores. Sodium hydroxide is the primary component of some types of drain cleaners. But read the label carefuly, drain cleaners come in many types and alot of them don't have sodium hydroxide. You can also buy sodium hydroxide online, it's sold for making home biodiesel or homemade soap.
After you made your solution, thoroughly clean your silver article and place it into the solution. Attach the positive terminal of a 3V battery to the article and dip the negative wire into the solution. Move the negative wire around the solution to give the silver an even coat, or keep it in a single spot to apply rainbow effects.
What's happening is the electric current is oxidizing the silver and causing it to pick up the sulfur dissolved into the solution. As it does this it thickens and alters the way light reflects off the surface. What color of light is reflected is determined by how thick the sulfide layer is. The thickness of the layer is determined by how long you anodize it. So you can control the color by controlling the time you apply the current.
The process can be used to tint silver items to give them an antique look or simply just to make them exotic colors.
Practice before you do this on something valuable.
If you make a horrible mistake, you can restore the silver by electrochemistry at this link http://www.youtube.com/watch?v=vGCx9HZwYBo
Always use batteries for this process to keep safe. Also don't use higher voltage batteries, you might end up "burning" a layer of silver off your item and ruining delicate designs.
We've done it with copper, but the color is not as brilliant, silver gives the best effect for the video. We haven't tried it with steel and aluminum just goes dark without getting color.
Thanks for watching, subscribe, rate and comment!
If you like my videos, check out http://www.nurdrage.com
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Just tried to do this experiment but it didn't work as expected. So I have a few doubts:
1 - Do you heat up the solution, or the oven (is it a oven or an automathic mixer?) has not anythig to do with the experiment?
2- Which are the exact cuantities for S and NaOH? or it does not to be so precise?
3 - Does the type of water has any influence? (destiled water, de-ionized?)
Cheers!!!
r
To format subscript use commacomma2commacomma, Ag2S
L
First, there is the addition of sulfur to the highly basic solution of sodium hydroxide. This forms an aqueous polysulfide from the action of the hydroxide molecules onto the Sx molecules. So you get something like
OH- + Sx --> HOSx-
The counterion being the sodium ions.
The sulfur being “soft” lewis base clusters around the silver. Eventually the positive potential is applied and the silver surface acquires a positive charge. The loss of electrons induces a half-cell reaction at the surface.
Ag --> Ag+ + e-
But since the polysulfides are already attracted to the surface they instantly react with the silver ions.
2Ag+ + 2HOSx- --> Sx + AgS + H2O
And this creates our silver sulfide layer.
The hydroxides are regenerated at the cathode when the water is electrolyzed.
2H2O + 2e- --> H2 + 2OH-
which then pick up the floating sulfur
OH- + Sx --> HOSx-