# Relationship between plating thickness, surface area, and ampere-hours

I am reading a PDF titled Electrochemistry for the Electronics Industry. I am having a hard time understanding the relationship between metals and the Ah (ampere-hour) relationship.

For the presentation example it is given that it requires 6.3 Ah to deposit 1 mil of gold (Au) on 1 ft^2 of surface or 2.6 Ah to deposit 1 µm of Au on 1 m^2.

Could someone explain how they determined those Ah amounts? It states that these factors are available from tables, but I cannot seem to find them.

I have attached the calculation I am talking about.

• To come up with the factors given, I think you would need to know what reaction is depositing the gold (how many electrons are exchanged to deposit one atom) and the density of gold. Everything else is just unit conversion. Commented Apr 26, 2021 at 16:28
• It seems to take more energy with large area/thickness ratio. Comparing volume of deposit 1mil/sqft is 16.4 times more than 1um/m2 yet only 2.4 times the Ah. So thicker platings so are more effective.(?) Commented Apr 26, 2021 at 16:43