Thermosets and thermoplastics containing PTFE are used in marine and hydropower applications due to their long service life and self-lubricity in dry and water-lubricated contacts. Their tribological performance is usually extrapolated from short, accelerated tests, which induces risks of inaccurate or incorrect interpretation.

The aim of this study is to investigate the tribological behaviour and development of transfer layers during long sliding tests (160 hours), corresponding to years of operation. To mimic operational shutdowns, the tests were stopped every 20 hours to study the evolution of the surface topography and transfer layers.

The wear rates of both materials decreased significantly with time. For the thermoplastic, COF decreased due to accelerated material transfer after 80 hours, highlighting the importance of long duration tests. The thermoset showed the highest transfer amount after 20 h and cause severe abrasive wear on the counter surface accompanied by a COF increase.