High-temperature fretting wear behaviour of cobalt alloys

Cobalt-based alloys are often used for components subject to high thermal and mechanical loads in corrosive environments where relative motion with small amplitudes occur. Use cases include parts and coatings at the turbine blade/disk interface, turbine blade shroud coatings, cast guide vane components as well as valve seat inserts in internal combustion engines and biogas generators. The friction and wear properties of the established Tribaloy alloys T-400, T-800 and a next generation high-entropy alloy with reduced cobalt content were investigated under ambient air atmosphere up to 700 °C using the SRV5 tribometer (Optimol Instruments Prüftechnik GmbH) fitted with the designated high temperature block. Analysis of the specimens include wear scar volume determination, scanning electron microscopy (SEM) and energydispersive X-ray spectroscopy (EDS).