Effect of contact pressure and load on wear of alumina

Wear experiments were conducted in air using self-mated alumina in a pin-on -disk configuration at different loads using balls of different diameters a s pins to maintain a constant value of initial Hertzian pressure. The selec ted initial load was kept constant for the rest of the sliding. Wear volume on the ball and the apparent contact pressures were calculated from the me asured wear sear diameters on the balls at regular sliding intervals. The r esults show reduction in wear coefficient with sliding distance, as the con tact pressure reduces (due to increment in the contact area). However, a go od correlation was observed between the normalized wear rate and the appare nt contact pressure, irrespective of the applied load, sliding distance, ba ll diameter and apparent contact area. This observation is explained based on the assumption that besides the asperities that deform plastically a lar ge portion of the asperities deforms elastically and carries the applied lo ad. It is argued that for a mixed elastic/plastic contact the number of pla stically loaded asperities, and therefore, the wear rate, should depend on the apparent contact pressure. (C) 2001 Elsevier Science B.V. All rights re served.