Coat thickness and coat thickness measurement

Coat thickness represents the central quality characteristic of a coating film. It influences all functional characteristics, as well as the corrosion protection of the coating film. For this reason, the observance of a required coat thickness is an essential prerequisite for coating quality.

When testing the coating thickness of a dry coating system the choice of measuring procedure is primarily dependent on the material combination of the coating system and substrate. The coat thickness should be identified directly after coating, in order to reduce the reject rate in the case of malfunctions. Measurement of coat thickness is specified in standards such as DIN EN ISO 2808. The methods of measuring coat thickness can be subdivided into those for dry films and wet films. In the case of dry film thickness a distinction is made between destructive and non-destructive measurement methods. Non-destructive methods include, for example, the beta backscatter method, x-ray fluorescence analysis and the eddy current method (amplitude intensive or phase intensive).