How to calculate/measure the thickness of zinc coating
August 14, 2008
Q. I would like to know what will be the thickness of the electroplating in microns, on MS sheets of flats, when 610 gms/sqmt of zinc is used.Vinod Kumar
Design engineer - India
August , 2008
A. Hi, Vinod. Usually electroplating is expressed in thickness but phosphatizing is expressed in weight because the meaning and usefulness of the term 'thickness' becomes compromised when you are speaking of a conversion coating which includes some dissolution of the original substrate, transition areas, and various different compounds.
But if this is zinc electroplating and the density of zinc metal is about 7.14 g/cm3, then you have 610/7.14 = 85.4 cm3 or .0000854 m3 of zinc spread across 1 m2.
So the thickness is .0000854 meters or 85.4 microns or 3.3 thousandths of an inch. That would be too thick for zinc electroplating and sounds more like galvanizing. Typically, and per spec, zinc electroplating would be 5, 8, 13, or 25 microns thick based on whether the service condition was mild, moderate, severe, or very severe.
Ted Mooney, P.E. RET
Pine Beach, New Jersey
August 15, 2008
A. 610 g/m2 is the often used equivalent of 85 microns used for hot dip galvanizing.
Can't imagine electroplating that thick!
galvanizing & powder coating shop
Calculating the cost of too-thick galvanizingMay 7, 2017
Q. I am galvanizing steel structures. The zinc micron thickness is higher than the standard coating. For example, I need 85 micron for steel whose weight is 10 ton and I am getting 100 microns for the same weight after checking by Elcometer. The difference of the microns is losing me money, so I need to calculate how much grams I am losing because of the difference of the microns.john picol
A. Hi John. If you multiply the thickness of the coating (100 microns) by the surface area you are coating, you will have the volume of zinc you are using. You can, if you wish, then multiply this by the density of zinc to convert the zinc usage to weight instead of volume.
Your unknown at this point, though, is how much surface area you are coating. Telling us the weight of steel you are coating doesn't help us because if we don't know the thickness of the steel we cannot convert its weight to its area.
As for how to reduce the thickness from 100 microns to 85 microns, we have many threads which address that issue, including:
letter 55032, "How can we minimize galvanize coating thickness",
letter 57597, "Reducing variance in galvanizing coating thickness"
and letter 45551, "Reducing coating thickness by adding nickel salts". Good luck.
Pine Beach, New Jersey
Striving to live "Aloha"