Densification kinetics of ZrO2-based ceramics using a master sintering curve

Abstract

With the aim to know the densification kinetics of ZrO2-based ceramics a master sintering curve for ZrO2 containing 3% mole Y2O3 was constructed. Zirconia (3% mole Y2O3) powders were prepared by a chemical method [1]. The compacts as obtained were uniaxially pressed at 200 MPa. The characteristic dimensions of compacts were 3.4 mm in length and 5.1 mm in diameter. A green density 40% of theoretical density was obtained after pressing. The shrinkage-temperature curves were obtained by dilatometric runs at different constant heating rates: 1ºC/min - 10ºC/min. To calculate the activation energy of sintering, several models [2] were applied to dilatometric data. These results were used to construct the master sintering curve (MSC) [3]. From this curve it was possible to characterize the sinterability of powders from the initial to final stages of sintering. Besides, MSC permitted to quantify the densification behaviour of these powder compacts. The results of this study can be used to predict the shrinkage/densification level of ZrO2 powders, and by this way to design a heat treatment to obtain a bulk ceramic with a predetermined density.