The general procedure will be explained for three contact pairs, the coated P4 and P8 as well as for the non
coated P10. All of them have been tested with 70 μm displacement amplitude and 1000 N load.
The COF gives a first good impression of the suitability of the tribo couple. For the specimen P10 we see three
main evolutionary stages. The first stage is a constant value over the run time. After approximately 200000 cycles
the COF starts to rise up to values of 0.4. After that it stays at this level for the rest of the test cycles. For P4 the
result gives a different impression. The COF stays at a very low level for the whole run time. It can be assumed that
the surface of P4 is not modified by wear processes. In opposite to the low COF of P4 P8 shows a high COF right
from the start of the test, at 200000 cycles it reaches its lowest value just before rising to higher levels at the end of
the test which lie in the region of the uncoated P10.