STEP Test measurement according to ASTM B764 and DIN EN 16866
The STEP Test (Simultaneous Thickness and Electrochemical Potential determination) is a long-standardized method for simultaneously determining individual coating thicknesses and the differences in electrochemical potential between the individual layers of a multiplex nickel coating system. The coating thickness measurement is carried out according to the Coulometric method, while the potential profile is captured using a silver reference electrode coated with AgCl. The potential profile is shown on the display; individual coating thicknesses and differences in potential can be viewed by positioning the cursor correspondingly on the plot.
To obtain comparable results with this method, the reference electrode must always be kept the same distance from the specimen; therefore, a special measuring cell is utilized. The silver reference electrode is a cone-shaped ring that forms the lower housing component of the measuring cell, further requiring only the obligatory gasket. This measuring cell design ensures a consistently uniform distance between the reference electrode and the specimen.