Two-Stage Master Sintering Curve Approach to Sintering Kinetics of Undoped and Al2O3-Doped 8 Mol% Yttria-Stabilized Cubic Zirconia

Eight mol% of YSZ is considered as one of the most promising electrolyte materials for solid oxide fuel cell. Small amount of Al2O3 is often added to 8YSZ to enhance its mechanical properties and conductivity, as well as to improve its sintering behavior. In this study, the activation energy and sintering kinetics of both undoped and 0.2-2.0 wt% Al2O3-doped 8YSZ are determined with the help of master sintering curve (MSC). It was found that a better representation of the sintering behavior could be achieved by constructing MSC over two consecutive densification stages with the relative density of 60% set as the boundary. From the activation energy values of the two stages obtained, two densification mechanisms were identified for the undoped and Al-doped samples. Based on literature data, the possible mechanisms that dominate the two stages were proposed and discussed.