Tribological evaluation of coatings/applications

Experimental model investigations to evaluate resistance to fretting wear or sliding/friction wear (including abrasive and erosive wear) are carried out, among others, with our test rig for the standardized determination of static friction coefficients. For this purpose, the contact surface pair to be tested is subjected to oscillating relative motion under normal force loading. The relative displacement amplitude can be set between 0.01 mm and 10 mm depending on the frequency. For measurement of small slip distances, relative displacement measurement using a laser extensometer is used.

With beginning surface destruction, the friction coefficient in the contact area generally increases. By integrating the dissipated work during a load cycle and accumulating it over the test time, the durability of a remedial measure against fretting wear or sliding/friction wear can be evaluated.

The geometries of the specimens are optimized for uniform distribution of surface pressure in the contact area. The planar annular contact on the standardized friction coefficient test rig with torsional loading, with inner diameter (D_i = 15 mm) and outer diameter (D_a = 30 mm), results in a nominal contact area A_nomT ≈ 530 mm².

Based on friction coefficient curves over the specific accumulated friction work, the time of surface damage can be determined at significant increases. In combination with surface examination using reflected-light microscopy or, for example, laser scanning using a confocal microscope, individual wear forms in the contact surfaces can also be identified.

• HRP2500 - Hydraulischer Reibwertprüfstand 2500