Electroplating Bath
Current density, deposition rate, plate thickness from bath composition.
How to use this tool
Predict how much metal an electroplating bath will lay down, and how thick the coating will be, from the current and time you run. Based on Faraday's law of electrolysis.
What to enter
- Metal: the plating metal; this sets its molar mass, charge per ion, and density.
- Current: the plating current in amperes (A).
- Time: how long the part is in the bath, in minutes.
- Plated area: the surface being coated, in dm² (1 dm² = 100 cm²); used to turn mass into thickness.
- Current efficiency: the percent of current that actually deposits metal (the rest is lost, mostly to hydrogen). 90–98% is typical.
Reading the result
You get the metal deposited in grams, the average coating thickness in microns, and the total charge passed. Double the current or the time and you roughly double the deposit.
Worked example
Nickel at 2 A for 30 min at 95% efficiency deposits ≈ 1.04 g over 1 dm², about 11.7 µm thick, having passed 3600 C (1.0 A·h).
Deposition
Deposited mass follows Faraday's law, double the current or the time and you roughly double the metal. Thickness is that mass spread over the plated area, so a bigger part plates thinner for the same charge. Charge passed is shown in both coulombs and amp-hours.
Faraday's law of electrolysis
Deposited mass m = (I·t·M)/(n·F), where I = current (A), t = time (s), M = molar mass of the metal (g/mol), n = electrons per ion, F = 96485 C/mol. Thickness = m/(ρ·A). Real baths lose efficiency to side reactions (hydrogen evolution); enter a current efficiency below 100% to correct.
Sources
- Faraday's laws; standard electroplating handbooks (Lowenheim, Electroplating).