On the abrasive wear of zirconias

Zirconia ceramics with different dopants, used to retain the tetragonal phase metastably, were evaluated to determine the effect of the difference in degree of transformability on the abrasive wear behavior. The abrasive wear tests, carried out on a multiple abrasive wear tester, showed that for two-body and three-body configurations the wear rate increases for higher normal loads and abrasive grain sizes. The specimen with low degree of transformability presented the worst behavior in every configuration owing to its low fracture toughness. For the three-body configuration, the specimen with intermediate degree of transformability presented the best behavior; this was associated with its higher hardness and flexural strength. For two-body abrasive tests, the change in wear severity conditions led to an inversion of wear behavior of the specimens with a high degree of transformability. The results obtained were associated with the microstructure generated, the physical and mechanical properties and the tetragonal to monoclinic transformation rates, since the stress induced transformation could be inhibited owing to the temperature developed in the contact between the zirconia sample and the abrasive material. Finally, the comparison between zirconia and white cast iron wear behavior under two different conditions revealed that the performance of zirconias was favorable only for low severity wear conditions and for intermediate and high degrees of transformability. (C) 1997 Elsevier Science S.A.