Investigation Into the Wear Films Formed on Certain Superalloys Between 20 and 600°C During Rotation in an Unlubricated Bearing

The tribological behaviour of Stellite 6, Tribaloy 700 and Tribaloy 400C have been studied during self-mated unlubricated rotational sliding between 20 to 600°C, at 3ms⁻¹ for 1 hour using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). Testing was conducted using a specially designed wear rig in which bearings and shafts of the materials were machined and tested within a furnace. Tribaloy 700 exhibited high bearing wear rates for all temperatures. Tribaloy 400C and Stellite 6 bearing wear rates generally decreased with temperature until very low wear rates were recorded at 600°C. The bearing wear rates appeared to be related to the formation of wear resistant oxide films often known as ‘glazes’. Adherent ‘glazes’ formed on Tribaloy 400C and Stellite 6 at 450°C and 600°C. However, ‘glazes’ formed on Tribaloy 700 showed poor adherence to the substrate causing high wear rates.