Extended studies on fretting wear criterion for coated systems with complete contact based on accumulated specific friction energy

This paper presents the results of basic studies investigating fretting behaviour in different coated steel-pairings.Performed on a test bench for the determination of friction coefficients using a standardized torsion test method, the completed experiments enabled the identification of variations in the temporal and tribological behaviour of each pairing due to the chosen coating.Characterised by flat annular contact surfaces which were pressed together with a pressure of 50 or 100 MPa, the samples were tested under alternating load with twisting angle amplitudes of 0.23° and 0.5° (or 46 and 100 microns slip, respectively).This technique enabled both optical damage (fretting, etc.) and strength-affecting mechanisms (damage of the substrate material) to be recorded.The results were evaluated using appropriate damage criterion, thereby identifying the accumulated dissipated friction energy as a fail-related physical quantity.