30 ElektroPhysik
4.
The difference
(
)
Xm
Xo
s
−
±
is the mean
coating thickness over the peaks; s is the
greater standard deviation of the two values
Xm
and
Xo
.
Method B
This method should be used for surfaces with a
roughness grade of max. < 20 µm (0.8 mils).
1.
Carry out a zero calibration of 10 readings
on a shot-blasted, uncoated substrate. Then
calibrate with a foil on the uncoated substrate.
The foil set should consist of a number of
individual foils of max. 50 µm (2 mils)
thickness each and should roughly
correspond to the estimated coating
thickness.
The coating thickness can be read directly
and should be averaged from 5 ... 10 single
measurements. The statistics function is
useful here.
Measurement on shot blasted surfaces
