The effect of test parameters on alumina wear under low contact stress

Abstract

A flat pin-on-disc wear test method in which a very low contact stress is applied was used to evaluate alumina wear behaviour. Wear tests were performed using alumina pin and disc with grain size of 8 μm in dry sliding conditions. The normal load, the sliding velocity and sliding distance were varied during the tests as follows: Load- varied between 5 N to 13 N, velocity from 0.5 ms −1 to 2.5 ms −1 and distance was up to 15.3 km. Two main wear regimes were identified, mild and severe wear respectively, with a transition region in between. A microabrasive mechanism was found to be responsible for the nucleation of cracks and initiation of wear. In the mild wear region, plastic deformation and tribo-film formation were the dominant mechanisms, whereas transgranular fracture and sub-surface crack formation were found to be the dominant mechanisms in the severe wear region.