Foils of uniform and defined thickness may serve as layer thickness standards if they are placed on appropriate substrate surfaces. They are frequently used to calibrate the widely spread electromagnetic layer thickness measuring instruments.
Usual designs:

10...500 µm of plastics
10...30 µm of bronze
> 500 µm of pertinax, brass

The reference area range is marked on the standards.

Coated substrates

n the case of some important procedures applied to measure the layer thickness (e.g. X-ray fluorescence method), the measurement values indicated include material-dependent parameters. For the calibration of these instruments, standards are used which must be made of exactly the same material as provided for the existing measurement task. For this reason and due to the variety of possible material combinations, it is expedient that interested users manufacture their own samples with their own technology and then have them calibrated at PTB.

Foto: Satz von Schichtdicken-Normalen mit galvanischer Nickelschicht auf diamantgedrehter Kupfersubstratoberfläche

Figure 1: Example of a set of layer thickness standards with galvanic nickel layer on diamond-turned copper substrate surface