The coating thickness could be detected by a magnetic way with a particular instrument called Magne-gage.
The lab is equipped with two magnetic instruments both calibrated on the following band: diamagnetic films on magnetic substrates.
Therefore they are suitable to detect e.g. zinc, chrome, cadmium, phosphate coatings etc…..mainly on iron or steels.
The mentioned instrument has a good sensibility and it neither destroys nor partially damages the analysed items.
For further information: UNI 2178/87 www.uni.com