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How to calculate average nickel thickness from current and time?

Q. What formula do I need to use to solve? A steel surface area 40 cm^2, is to be nickel plated. What average plating thickness will result if 12 A is applied for 15 minutes in a cyanide electrolyte bath?

Mehdi Mohammadi
student - Loughborough, UK
2007

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I've never heard of a cyanide nickel plating bath, Mehdi, but the principal formula you need for this is Faraday's Law of Electrolysis, which states that one gram equivalent weight will be deposited for each 96,485 amp-seconds. This quantity of electricity is sometimes called a Faraday. So you can convert your amp-minutes to Faradays or gram equivalent weights. Then from the atomic weight, valence, and density you can come up with the volume of metal deposited.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

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Q. Hello,
We are doing nickel plating to bucket handle. But the plating takes longer than we expect. Can anyone help me about the chemical composition of the wire which will attract nickel plating in maximum time? Or any particular process? BTW, we're using HB wire and using copper before nickel plating as standard procedure.
Thanks

Joydeep Mukherjee
- Kolkata, India
February 28, 2020

A. Hi Joydeep. We may have a translation or typographical error, but plating speed/thickness is not in proportion to the type of substrate material, but to the applied amp-hours of current in accord with Faraday's Law.

Please give us a calculation of the time you think it should take to get the desired plating thickness in accord with Faraday's Law, vs. the actual time it is taking. Also tell us what current density you are plating at because excessive current density can lead to burning.

The Metal Finishing Guidebook has an "Electrochemical Equivalents" chart which incorporates the conversion factors for valence, atomic weight, density, and the 3600 seconds in an hour into the Faraday's Law calculation, yielding the answer that at 100% efficiency you will deposit 1.095 grams [0.039 ounces] per amp-hour, and that it will take 19.0 amp-hours/ft2 to deposit a thickness of 0.001".

If this reply or this page uses terms or concepts which you don't yet understand, let us know so we can work our way through it. Good luck.

Regards,

Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey