THE TENSILE CREEP-BEHAVIOR OF SUPERPLASTIC TETRAGONAL ZIRCONIA DOPED WITH SMALL AMOUNTS OF SIO2

The constant stress tensile creep behavior is reported of a tetragonal zirconia (3Y-TZP) with a grain size of 0.27 mu m as a function of SiO 2 addition up to 2.5 wt%. The effects of SiO2 addition are classed int o two definite regimes. In the first regime, up to 0.3 wt% additions, both stress exponent, n, and apparent activation energy, Q, decrease s teeply and strain rate, (epsilon) overdot increases also steeply as th e amount of SiO2 increases. In the second regime, with additions more than 0.3 wt%, n and Q remain almost constant while (epsilon) overdot i ncreases gradually as the amount of SiO2 increases. The appearance of the respective regimes is closely correlated with grain boundary micro structures modified by the SiO2 addition. (C) 1997 Elsevier Science S. A.