Letter 19099

Black Pennies [Texas] 

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I am nickel plating a penny for my science fair project. When I do the experiment the penny gets plated with nickel, but then it turns black. Why?

Courtney
- Carrollton, TX, USA

Are you using a single 1-1/2 volt battery?

 
Ted Mooney, P.E.
finishing.com Inc. - Brick, NJ

Mr. Mooney,

Thank you for taking the time to look at my question. You asked me if I was using a 1 1/2 volt power source. I am using a regular 1 1/2 volt battery as my power source.

Thank you again!

Courtney
- Carrollton, TX, USA

A blackish color is usually what platers call "burning". It occurs when the chemistry can't keep up with the electricity being supplied. Although a part would never "burn" at 1-1/2 volts in a commercial plating tank, it can happen in a student plating project if the plating solution is so dilute or so low in metal concentration that there is not enough metal available to plate out so that the electricity is diverted into seperating water into hydrogen and oxygen instead.

You said that you are nickel plating (which is not covered by our guidelines for student plating) so I guess I have to ask what solution you are trying to dissolve nickel into? If you are trying to nickel plate from a vinegar solution, vinegar probably isn't strong enough to dissolve nickel. Where are you getting the nickel from?

Is there a reason you can't do the copper or zinc plating we talk about in the letters and FAQs here?

 
Ted Mooney, P.E.
finishing.com Inc. - Brick, NJ

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