2.3. Abrasion tests
The dry abrasion wear testing was performed with a rubberwheel
abrasion test equipment, which is a modified version of
the ASTM G65 standard. The test apparatus has been presented
and described elsewhere [8]. In the test the steel block with a
coated surface was pressed against a rubber-lined wheel at anormal load of 23 N. The test duration was 1 h, which equals to a
total wear length of appr. 6 km. The abrasive was quartz sand with
the size of 0.1–0.6 mm. The particles are blocky and sharp in their
shape, due to preparation of the sand by crushing. The hardness of
quartz is 7 in the Mohs scale.