Effect of Grain Size and Test Configuration on the Wear Behavior of Alumina

Abstract

The effects of grain size on the tribological behavior of alumina were investigated. Alumina specimens with three different grain sizes, namely 4, 8, and 14 m, were used as pins and disks in a flat‐pin wear test in which the apparent contact area was maintained constant during the test. In contradiction with previously published reports obtained with the regular round pin, our work has found that in this case the alumina wear decreases with increasing grain size. The evidence presented here suggests that the effect of grain size on alumina wear behavior is strongly influenced by the test configuration. Small grains and large grains exhibit two different wear mechanisms: brittle fracture such as grain pull‐out and microchipping as well as abrasive wear are the dominant mechanisms in the small grain size alumina, whereas plastic deformation plays a significant role in the wear behavior of coarser‐grained alumina.