EFFECT OF MICROSTRUCTURE ON THE WEAR TRANSITION OF ZIRCONIA-TOUGHENEDALUMINA

The mechanical properties of alumina ceramics can be improved by the a ddition of pure or partially stabilized zirconia particles. In the pre sent study, the wear characteristics of zirconia-toughened alumina (ZT A) composites under a non-reactive fluid (paraffin oil) lubricated con dition were investigated. The wear transition load (i.e. the load at w hich a rapid increase in wear occurs) increased with increasing zircon ia content up to 20 vol.%. The transition from mild to fracture-contro lled wear of ZTA depends on the material properties (e.g. hardness, el astic modules), the contact conditions (e.g. hertzian stress, coeffici ents of friction) and the microstructure of the material. The effect o f the microstructure on wear was demonstrated and a Hall-Petch-type re lationship between the microfracture stresses and the grain size was f ound. The effect of the grain size distribution on the wear transition load was also shown.