Reliability of wear volume measurement approaches in relation to the effect of surface finish on friction and wear of Al2O3

Wear measurements are notoriously variable. Even the experiments with the same type of material and test machine can give significantly different results. Such discrepancies are mostly due to a lack of adequate control of test conditions and unreliable measurement techniques. Specification and control of certain tribological quantities are a necessary prerequisite of obtaining reproducible and comparable results. To proceed forward in this direction, it is essential to review and analyze the existing test procedures and measuring techniques. In this study, the authors investigated the reliability of the most common wear volume measurement approaches and explored the influence of surface finish on the friction and wear performance of Al2O3 ceramics. The wear tests were performed with a pin-on-disc machine on polished and ground surfaces of Al2O3 disks. The wear volume was measured from height displacement, weight loss, and from worn surface profilometry. The results indicated that the wear volume measurements by surface profilometry and height displacement (by transducer) were highly reliable. The wear rates of ground and polished alumina were in the order of 10(-7) mm(3)/m . N. Finally, for the specific surface roughness range (Ra = 0.03 to 0.4 mu m) explored in this study, the surface finish was only important during the initial run-in period