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Electroplating with Copper Sulphate, Nitrate, or Chloride
Q. I am doing a project on electroplating and I'm going to use Copper sulphate, copper nitrate [affil links], and Copper Chloride. I'm going to see which is more efficient in plating aluminum. I have ordered 100 g of each. I will have to do 10 trials of each. I was wondering what would be a constant voltage I could use and how do I calculate the amount of water to mix with each to get a 1 mol solution. Also how long should each trial last.
Trey McCants- Seneca, South Carolina
1999
A. Uh, Trey, uh who designed this experiment? :-)
I don't know why you intend to use aluminum, but . . .
You cannot properly electrplate onto aluminum without special techniques and chemicals you don't have access to (zincating specifically). Further, you cannot electroplate a more noble metal (copper) onto a metal which is less noble (zinc, aluminum, or steel) without totally screwing up your experiment because it will spontaneously plate out without external electricity. Ideally you should use real silver dimes or quarters as your substrate, although nickels or modern dimes or nickels will suffice.
A 1-1/2 volt D-cell battery will do fine. You ideally should put a resistor in series to limit the current to no more than about 5 amps per square foot, and use a pocket milliammeter to measure and verify the current.
I'm sure you know what a molar solution is and are really asking the formula weight of these three salts. Well, copper sulphate [on eBay or Amazon]is CuSO4.5H2O; copper chloride is CuCl2.2H2O; I don't know how hydrated copper nitrate is, but the formula will come with the material.
The electroplating should probably go on for about 15 minutes, and Faraday's Law of Electrolysis ("96,485 amp-seconds will deposit 1 gram equivalent weight") will predict the thickness of the copper layer for you. Good luck.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
1999
(to help readers better understand the Q&A's)
David's question is somewhat abstract such that we can't tell whether this is a student project or an inquiry by an industrial electroplater. Tom apparently believes David is an industrial electroplater, not a student, because cyanide is a very dangerous chemical completely inappropriate for use by students!
Q. Dear Sir:
I was planning to have a copper plating on an iron steel. I tried using sulfuric acid and copper chloride solution but the output is a black coating. What should I use to have a clear copper plating and what is the typical current and voltage in plating with copper.
David CabaÒal- Iloilo City, Philippines
2001
A. Cyanide copper plate at 10-30 amperes/square foot, 1-5 volts.
Tom Pullizzi
Falls Township, Pennsylvania
2001
Q. Hi I am a Y12 IBDP student doing electroplating for a chemistry IA, my variables are using copper sulphate and copper nitrate in electroplating so I was wondering how does nitrate and sulphate ions (in their respective copper salts) affect the mass of copper plating?
Justine Laine- Hong Kong
September 17, 2017
A. Hi Justine. The single most important thing to understand regarding electroplating as a science/chemistry experiment is Faraday's Law of Electrolysis, i.e., that 96,485 ampere-seconds will reduce at the anode (and oxidize at the cathode) one gram equivalent weight of material.
Please look it up in several sources, try to thoroughly understand it, and you'll probably know more than your teacher and have the firm grounding to be able to answer to all sorts of electroplating questions of this nature. Best of luck!
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
September 2017
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