Chemical aspects of wear of alumina ceramics

In our investigation, the effects of the tribochemically-induced dissolutio n of alumina ceramics and modulation of near-surface forces (surface charge ) within the tribocontact were studied. The wear and friction behaviors of alumina were investigated using a reciprocating sliding test in different c hemical environments. The samples for the tests were hemispherical pins and plates of polished alumina, both prepared by a near-net-shaping method. The sliding tests were conducted in water-based Liquids with different pH v alues or with the addition of a polyelectrolyte to control the surface char ge at solid surfaces. The coefficient of friction was continuously recorded during the tests and the wear-loss was subsequently determined for all sam ples. The results show a significant effect of the chemical agents on the c oefficient of friction as well as on the material-removal rate in different aqueous media. The results are discussed in terms of the chemical and elec trochemical properties of the materials in the tribocontact. (C) 2001 Elsev ier Science B.V. All rights reserved.