Studies on sintering kinetics and correlation with the sinterability of 8Y zirconia ceramics based on the dilatometric shrinkage curves

Abstract

Prediction of the dominant sintering mechanism and corresponding temperature regimes become important in arriving at the optimum sintering schedule of ceramics. The sintering kinetics of 8Y zirconia (8YSZ) submicron powders, with particle sizes ∼205 nm, has been evaluated through, (i) constant rates of heating and (ii) master sintering curve (MSC) technique. Slip cast green 8YSZ compacts, close to 50% of the theoretical density, have been subjected to dilatometry, for recording the shrinkage behavior, at constant heating rates of 5, 10 and 20 °C/min. The kinetics of the corresponding sintering process has been evaluated by estimating and comparing the apparent activation energies ( Q ) from the constant heating rate technique, and MSC approach. The observed apparent activation energy (∼350 kJ/mol) suggests grain-boundary diffusion to be the dominant mechanism in sintering of 8YSZ ceramics.